Maybe you’re thinking, “There’s nothing I can do until I actually get there, right?” Not true. If you didn’t interview with the person who will be your immediate supervisor, contact her immediately. Send an introductory e-mail, and while you’re at it, ask her if she has any materials you can review that will better prepare you for your first day. Has your new company been in the news lately? Include a line in your letter that shows you’ve been keeping up. This short note will probably take 10 minutes to compose and will do wonders for your boss’s preliminary perception of you as a competent and proactive new hire.

If your manager sends materials, be sure to read them carefully. Common sense, right? Well, sad to say, I was caught with my pants down when, on my first day of a new job, my manager asked me a question about the annual report he’d mailed. I’d only skimmed the report and didn’t have it in front of me, so I choked. Hopefully you are a better BS-er than me, but knowing the facts can never hurt—especially in a new work situation. Also, if your new manager mentions any important team meetings or conference calls that will take place before your first day, volunteer to join them via telephone. This might be difficult to do when you’re still sitting at your desk in your old company, but try to swing it if you can. Your new colleagues will be impressed to see you involved before you’re on the company’s clock, and, next thing you know, everyone on the team will be looking forward to your start date.

Camille Lavington, a personal marketing consultant and author of You’ve Only Got Three Seconds, says that when you first meet someone, you only have three seconds to make an indelible impression. The moment an individual sees you, he evaluates your clothing, hairstyle, grooming habits, facial cues, and posture. Without even thinking about it, he’ll decide whether he wants to get to know you better and whether you are worthy of being taken seriously. No matter what you say from that point on, his opinion of you will be heavily influenced by his initial perception. Three seconds is not a lot of time. Plus, during your first day at a new job, you will meet a lot of people who are important to your future success. You will also have to cope with one major disadvantage that you can’t do anything about—your age. Even if you alter your appearance or demeanor, you will probably still look like a twenty-something. Some people will expect you to act flaky, immature, or entitled because you are young, and the burden is on you to prove them wrong. Needless to say, you’ll want to prepare for these challenges before you arrive.

Let’s start here. Like it or not, most of the corporate world is conservative at heart. On your first day, show up wearing a clean and neatly tailored suit in an appropriate color such as black or navy blue, even if the rest of the company dresses in business casual. You might be overdressed, but I guarantee no one will criticize you for it. Rather, your colleagues will respect that you mean business, and your boss will be proud to introduce you around the company. Besides, isn’t it easier to act professionally when you look the part? I know that when I’m sitting down to a meeting and I’m wearing khakis, I sometimes forget to cross my legs. I never do that when I’m wearing a suit. If your company is business casual, you can taper off the suit-wearing after a week or so. However, if the dress is mixed, I suggest staying with the suit. You’ll be able to compete with the best-dressed people in the company, you’ll appear older, and you’ll look like a million bucks when you run into the CEO in the elevator. A colleague once told me that if I dressed like the VPs, I would become one faster because people would be able to picture me in a higher position.

I’ve also heard that women primarily look at shoes and jewelry when evaluating other women. Don’t have a lot of money? I recommend investing in three good pairs of dress shoes and a few pieces of simple, but high-quality gold jewelry. If you’re afraid your commute will kill your feet, wear sneakers on the way to work and change before stepping into your office building.

The best advice I have for guys is to shave often, don’t wear ties that scream for attention, and don’t knock people over with your cologne. And forgive me for saying this, but lose any visible body piercings. I know it’s not fair, but the fact is that a man wearing an earring has a certain connotation in the corporate world, and something that tiny should not be allowed to compromise your corporate persona.

In recent years, twenty-something employees have been guilty of taking business casual dress codes to new extremes of casual. Folks, business casual should be defined as something you might wear to a place of worship—for example, a knee-length skirt, a short-sleeve blouse, and dress sandals for a woman and a pair of chinos and a polo shirt for a man. Jeans, flip-flops, T-shirts that advertise, and in general anything wrinkled, stained, torn, or too revealing of certain body parts should be reserved for a Sunday afternoon football game in your living room.

In addition to being vigilant about your style of clothing, you should watch your use of workplace accessories. Once upon a time, I carried a chewed pen around to all my meetings, until a coworker lightly asked me if my pen tasted good. I never made that mistake again!

Your first week at a new job will be a whirlwind of new people and situations. When I jumped from an office with 300 people to one with more than 3,000, I was so confused, I had trouble remembering anyone’s name for a few weeks. Nevertheless, as I mentioned previously, the first few moments of interaction between you and other people will shape their appraisal of you. So when you are introduced to new colleagues, remember to make eye contact, smile, and shake their hands firmly. Ask them their names, and find out what they do for the company. Jot these things down quickly, along with anything else that might help you remember them. Engage in small talk freely if the conversation goes that way, staying away from thorny political issues that could get you into trouble. Show that you are interested in them by paying them sincere compliments or asking appropriate personal questions.

In these first conversations, the goal is to project enthusiasm, confidence, and an aura of respect—no matter who you’re meeting. I’ve seen new people come into a company and put their best face on for the executives, while disregarding everyone else. This is not smart. A corporate persona is nothing if not consistent. Besides, you won’t know who the company influencers are at the beginning. It’s a good bet to pay special attention to administrative assistants. These individuals tend to have the executives’ ears, and they know how to work the system. When meeting or dealing with “admins,” be polite or even deferential. They may turn out to be the most important allies you have in the company.

If your manager doesn’t send an e-mail welcoming you to the department, it’s a nice gesture for you to introduce yourself this way. The message should be no more than a few lines containing a brief summary of your background and stating how happy you are to be working there. Create an e-mail signature, and add it to your outgoing messages so that your colleagues can note your full name, title, and contact information.

If you thought everyone in the corporate world spoke your language, think again. The business world’s language is one of subtlety, filled with euphemisms and pet phrases to cleverly disguise what people actually mean. Because you wouldn’t visit a foreign country without a pocket translator, I’ve provided one here for your convenience that covers office lingo. Study these basic phrases at the beginning of your journey, and you’ll be talking like a native in no time.

So in other words: “We must take advantage of the fact that someone has already come up with a working concept that everyone in the company buys into. You should use this concept to convince the higher-ups that your project will make the company money.”

Imagine being shown to your new office—a windowless cubicle. A dead plant is there to greet you, along with crumbs of dirt all over the carpet. The telephone cord is hopelessly tangled and you don’t see a computer anywhere. Welcome to the corporate world! Don’t be offended that your new company didn’t take the time to set up a nice workspace for you—just move on. The first thing to do (after cleaning up the dirt and setting up your computer, of course) is to get your phone and computer systems in working order so that people can get in touch with you immediately. Providing for the electronic health of your cube is also a good exercise to find out who takes care of such things in the company. Once your voice mail is functional, leave a short, friendly, and professional greeting. Speak slowly and block out as much background noise as possible.

Next, it’s time to get some office supplies, so make your way over to the admin’s desk. Proceed with caution. No matter what level in the company you are, do not assume that it is the admin’s responsibility to order your supplies. Ask her how you can order them, and see what she says. Pouting if you have to do it yourself is not a good idea. Look at it this way—at least now you can get those nifty dry erase markers you like!

Hooray, now it’s time to decorate! Just keep in mind that, although your cube or office is the space you work in, it belongs to the company. It’s fine to place a few framed photographs on your desk and/or pictures on the walls, but don’t overdo it. Put all other personal items, including personal paperwork, in a single desk drawer that you can lock at night. You never know when your boss will need something from you after hours, and will take it upon himself to come looking for it. Also, be careful how much food you keep in your cube or office. Laugh if you want, but you don’t want to be the one blamed for the mouse that sends 30 colleagues screaming into the hallway.

Plan strategically how you want to organize your desk. I know a lot of people who believe that having a cyclone of a desk makes them look as though they are so busy that they just can’t keep up with the work raining down on them. That may be true, but it also makes them look terribly disorganized. Being neat and efficient is part of your corporate persona, so even if you’re the brilliant “absentminded professor” type, you might want to modify your habits. Create practical online and offline filing systems that allow easy access to regular materials and can be used readily should a coworker need to take over a project. Remove documents from your mailbox and e-mail inbox as soon as you are finished with them, and write notes in a book or on a dry-erase board to avoid a sticky-pad explosion. I think you’ll find that keeping order is easy if you start at the beginning, before reams of paperwork are flooding your desk.

Whether you’re thrown headfirst into a project or left alone to stare at the walls of your cubicle, the most important thing you can do at the beginning of a new job is to pay attention. You don’t have to be a CIA operative to harness the power of smart observation. Simply keep your eyes and ears open, and you will become an expert at mastering the corporate culture of which you are now a part. I know you’re eager to let the company know who you are and what you’re all about, but keep in mind that the most successful employees are the ones who effectively assimilate into their company’s culture.

Do your best to lay low in the beginning. Take the time to study every aspect of your new company, including how people present themselves, how they work together, and how they interact with executives, managers, and clients. What are the written and unwritten rules of engagement? It’s particularly useful to watch how employees conduct noncompany business during the workday so that you can get a sense of how personal breaks, e-mail, and phone calls will be tolerated. As you learn, begin to adapt your behavior and work style to suit the work environment.

Examine your company’s Website, annual report, and recruiting materials for clues about its mission, goals, image, and values. Is your company more focused on forging ahead in the market or delivering superior customer service? Is the culture guided by competition or cooperation? Is it more important for employees to be solely focused on hard-core business realities or to be well-rounded in their professional and personal lives? If these things are difficult to determine through written materials, you may need to scope out your work area. On my first day at a Fortune 500 company, for example, I noticed a book of photographs on my boss’s desk. The book, which my company had produced, featured pictures of children in the on-site daycare center. The following week, area schools were closed. I was not surprised to see my colleagues bringing their children into work for a company-sponsored holiday camp. In no time at all, I had become aware of the importance of family in their corporate culture.

Remember that although the corporate world is the same in many ways, cultures vary dramatically from company to company. Just because it was perfectly acceptable to order snacks for an afternoon brainstorming session at your old place of business doesn’t mean that your new boss will consider this to be a legitimate expense. Developing a good understanding of your new company’s culture will unquestionably serve you well as you look for ways to make a contribution.

When you’re grooming your corporate persona for a multitude of new colleagues and spying on the company culture, doing right by human resources may seem like the least of your challenges. If you’re tempted to think about it this way, just remember that HR hired you, and they also have the power to make trouble for you, if so inclined. Learning the ropes early in your career with a company won’t take much time, but it will inevitably save you major headaches later on.

On your first day, you will probably be asked to fill out a “Hello, My Name Is” sticker and show up to an orientation for new hires. This event will typically feature overly enthusiastic guest speakers, generic orientation videos, and a tedious page-by-page review of a mountain of paperwork. You will leave the building at the end of the day, head spinning, with an information packet. Your first instinct might be to toss it in the dumpster on the way to your car. But, instead, you must take the folder home and reread every word. HR has probably asked you to immediately sign a few legal documents. One will probably be a tax form that the company needs in order to pay you, a second might be a non-compete agreement (if you leave the company you won’t go to work for a competitor for a set period of time), and a third could be a confidentiality agreement (you won’t share the company’s proprietary information). It’s important to understand what these documents say, so ask your parents or a friend to help you if you have to. Getting these documents back to HR the next day will serve several purposes: You won’t lose or forget about them, your assimilation into the company community will be hassle-free, you will look like a responsible and efficient employee to the “Job Gods” in HR, and you will erase any chance of anyone going to your boss in order to collect your delinquent paperwork.

The new hire folder often includes an employee handbook that outlines company policies, such as initial performance review periods, compensation, dress code, smoking and drugs, sexual harassment, and company benefits. Treat this book as though it’s your new best friend for a few days. Don’t leave it on the train, and avoid the urge to stuff it in a desk drawer without reading it. True story: My friend Zach, who worked for a Fortune 500 telecommunications company, was fired after an HR representative caught him smoking on company grounds. Zach was outside the building at the time, but his company had a zero-tolerance smoking policy, which was covered in the employee handbook. Although his company’s reaction was extreme, Zach was dismissed legally and couldn’t do anything about it. The best way to steer clear of these situations is to know where you stand from the get-go.

Fewer aspects of your job are as important as the number of days you get to spend away from it. That said, you should read and understand your vacation policy up front. Many companies give a standard two weeks per year for new employees, but policies on personal days, paid holidays, sick and bereavement leave, and short-term and long-term disability leave vary. Some businesses also limit the amount of vacation time you can take during your first few months of employment. I accepted my first corporate job six weeks before my college graduation, and, lo and behold, two days before I was scheduled to take off for the ceremony, I ran into a snag with HR because I hadn’t cleared unauthorized vacation days ahead of time. By the way, unless you do not have any other choice, don’t plan any vacations during your first three months with a company. Remember your corporate persona and consider how jetting off to the Caribbean within weeks of your start date will look to company veterans who haven’t taken a vacation in two years.

In order to encourage better work/life balance, and as a response to technology that allows workers 24/7 accessibility, many organizations are implementing flextime and teleworking policies. Flextime arrangements might include part-time or compressed schedules (for example, the employee works 40 hours from Monday to Thursday and takes Friday off) and job sharing, in which a full-time position is split between two people. Teleworking or telecommuting, of course, means that, for at least part of the business week, an employee works from a remote location—often the home. Talk with HR and/or read your orientation materials to understand how your organization’s flextime procedure works. Note that even if the company doesn’t have an official policy in place, if there are other people in your department who are already working flexible schedules, it shouldn’t be unreasonable for you to hop on the bandwagon—provided you can honestly say you have the self-discipline to work productively without supervision. In making an argument for flex time, always put the company first. For example, if you want to work from home one day per week, tell your boss that you plan to get more work done in less time due to the minimization of distractions and not having to commute. Ask for a trial of the new arrangement, and prove the cost-savings by working much more efficiently on that home day than you do during your in-office days. Make sure that you are always accessible via e-mail and cell phone during the business day, and report project status often so it’s easy for your boss to keep tabs on you.

In our 20s, we’re accustomed to abusing our bodies and getting away with it. Given that we never get sick and think we’re going to live forever, it’s easy to take health benefits for granted. However, because group insurance plans and flexible spending accounts (which allow you to deposit part of your salary, pre-tax, into a special account for medical expenses), are notoriously complicated, it’s in your best interests to scope out the lay of the land in case you urgently need a health service. Familiarize yourself with the benefits you are entitled to and make sure you review your coverage in depth before heading to the doctor’s or dentist’s office. Trust me, it’s well worth your time, because once you make a claim the insurance people decline to cover, squabbling with them quickly becomes a frustrating and time-consuming process. Also, playing tug-of-war with an HMO during office hours or inviting your HR benefits administrator to referee are not optimal strategies for minding your professional reputation.

Are there ways your company will contribute to your care and feeding beyond the bimonthly paycheck? Yes, indeed. Most companies offer a 401(k), which allows employees to contribute a portion of tax-free income to a savings account. The company will also match a percentage of your contribution, which you get to keep if you stay there an allotted period of time. I could devote an entire book to a discussion about 401(k) plans, but instead I’ll share a few tips for leaving your financial future in the hands of your new company:

If you work for a public company (a corporation that issues shares of stock to members of the general public), you might be lucky enough to get stock options. A stock option gives an employee the right to buy or sell shares of company stock at a specific price for a specific period of time. You can typically get an excellent deal on your company’s stock by exercising options—but tread carefully. Some employee stock purchase plans have stringent requirements for exercising options, including narrow windows during which you can buy or sell your stock.

You might think this one is a no-brainer. You spend money on behalf of your company, and then HR pays you back, right? Unfortunately, corporate expense reimbursement can be fraught with peril. On the one hand, you want to get what’s owed you. On the other hand, you must also care for your reputation by keeping company expenses down. Because navigating most expense report software programs is a chore, get to know your company’s tools before you have items to submit. You should also find out early if corporate expenses must be charged on a particular credit card, or if you are required to use certain vendors in order to be reimbursed. When traveling or eating out on the company’s dollar, choose the middle-of-the-road option instead of the most expensive. Most importantly, don’t pad your expense reports. Read your policy in detail to determine what you will be reimbursed for, and don’t submit anything that doesn’t meet these requirements. And please don’t lie. As enticing as it is to take your significant other out to dinner on the company after you return from a business trip, don’t do it. The $50 you will spend today is a drop in the bucket compared to the months of salary you’ll lose if you’re caught.

Depending on your position, your new company might offer to pick up the tab for your cell phone and PDA. Joining the company plan can save you big bucks, but you should be prepared for calls and minute usage to be monitored. By paying for your cell phone, your company assumes that you will be using it to make business calls. If you regularly run up international and roaming charges calling your family in Greece or your friend who owns a dude ranch in Montana, you should probably keep a personal cell phone as well.

Now that you understand your company’s policies, it’s time to bid adieu to the Job Gods and get to work. In general, the less human resources is reminded of your existence, the better. Think of HR as a sleeping baby you don’t want to disturb. Go about your business doing what you’re supposed to do, but keep the noise level to a minimum.

One of my favorite managers used to say that perception is reality, and there is nothing stronger than a perception formed on the basis of a first impression. Whether you have a clock-watcher as a boss or not, it’s crucial that you are on your best behavior during your first month at a new job. Be aware that everyone is watching you, so make sure to arrive on time for work. It’s not a bad idea to be seen eating lunch at your desk a few times so that your coworkers keep that image in their minds. If you do go out, don’t run over the allotted hour, and refrain from midday workouts at the gym until you’re well established at the company.

At the end of the day, carefully watch what time people in your department leave the office. You should aim to depart at the midpoint. You don’t want to be the first one out the door, but if you’re the last one, you’ll set a precedent that you are willing to work late for the rest of your days at that company. Also, because many employers think they are entitled to work twenty-something employees to death, make sure your boss and colleagues see early on that you have a life outside business hours.

In this age of instant accessibility, flexible workplaces, and virtual teams, it may seem ridiculous that anyone should be chained to a desk between 9 and 5 every Monday through Friday, but if your company is one that’s still rigid about physical attendance, you may not have a choice. My friend Harry told me that his company’s CEO stood at the window of his corner office and watched to see how many cars rolled through the gate one minute after 9 a.m. Remember that half the battle is showing up, so don’t get caught by someone’s attendance radar.

If you are fortunate to have a flextime policy, don’t take advantage. Work the requisite number of hours, and while you’re on the clock either in the office or at home, stay busy doing the company’s business. This includes resisting the temptation to have three Meebo windows, your Facebook profile open, and your iPod headphones blaring. I hear that you are an excellent multi-tasker, but your boss, who could be looking over your shoulder, doesn’t know you that well yet. Staying away from distractions will be difficult in the beginning, particularly because most managers have no clue what to do with new employees—it’s either too late to involve you in an existing project, they do not trust you to handle anything that’s on fire, or they do not have time to show you the ropes. Nevertheless, you don’t have to sit at your desk twiddling your thumbs. Offer assistance to your managers and colleagues, and if anyone takes you up on the offer, make sure you do a better job than expected.

Inevitably, your days at a new job will involve administrative work in some shape or form. If you’re a recent graduate, there is a good chance the company sold you on using your existing skills to do meaningful work. Therefore, you are probably insulted to be answering phones for the price of a college education. My best advice is to think of your time as an administrative assistant as a rite of passage. Everyone must do it, and by the time you emerge from your mountain of executive e-mails, you will appreciate the mundane tasks that go into running a business, and you will also have the knowledge and experience to contribute in a consequential way. If you’re a mid-level employee and someone requests that you assist with administrative work, do it with a smile. Yes, I realize that you paid your dues a long time ago, but that person might not know you blistered your fingers making 7 million photocopies as an admin. Trust me, you won’t be doing it forever. Provided you command a higher salary than an admin, the company will want to leverage your skills elsewhere.

When your manager involves you in a project that includes coworkers, don’t jump in and take over. Do more than your share of listening and ask for direction from your teammates rather than suggesting your own course of action. Nothing turns people off like a newbie who waltzes in and says, “Well, at my old company, we did it like this.” The second this comes out of your mouth, people will think that if things were so swell at your old company, maybe you should go back. This is the last thing you want. For the sake of your corporate persona, use your first projects as an opportunity to observe how things are done at your new company. You’ll have your time in the sun soon enough.

During your first weeks, be especially careful about using company resources such as FedEx and international calling for personal reasons. Use any free time to research your position and brainstorm project concepts. Reading is fine too, but keep the content to industry publications, human resources material, or anything related to the company or your job. Show your boss what you’ve learned by sharing ideas, highlighting key points in printed articles, and asking questions. She will think that you are hungry and prepared to hit the ground running—which, my friend, is exactly how stellar reputations are made.

Your new position may require business travel, and the first time your boss tells you that you’re shipping out of town, you’ll probably jump for joy. After all, this is exciting stuff. Not only will you be escaping the office, but you’ll also be spending your company’s dime to sleep in a king-size bed by yourself and sample cuisine from a new city’s finest restaurants. And don’t forget about those free mini-shampoos in the hotel!

After a while, the magic of business travel wears off. You find that your trips away from the office involve working more hours, not less. You return, exhausted, with a bag full of dry cleaning and a week’s worth of e-mails to catch up on. But for better or for worse, business travel is a part of life for many corporate employees. Here are a few tips to make your trips more bearable:

I’ve logged hundreds of business trips, and I still get stymied by some of these. I’ll never forget the time I arrived at JFK Airport only to find that my flight to Washington was departing from La Guardia. If only I had reviewed my itinerary ahead of time! Learn how to travel smart, however, and your experiences as a road warrior can add a rewarding new dimension to your job.