1. Start your form with a header element:

<header>
    <button type="object" name="open_commercial_entity" 
         string="Open commercial partner"
         class="btn-primary" />
</header>

2. Add a sheet element for content:

<sheet> 

3. Put in the stat button, which will be used to archive the record:

<div class="oe_button_box" name="button_box">
    <button name="toggle_active" 
        type="object" class="oe_stat_button" 
        icon="fa-archive">
            <field name="active" widget="boolean_button" 
                 options="{'terminology': 'archive'}"/>
    </button>
</div>

4. Add some prominent field(s):

<div class="oe_left oe_title">
    <label for="name" />
    <h1>
        <field name="name" />
    </h1>
</div>

5. Add your content, You can use a notebook if there are a lot of fields:

<group>
    <field name="category_id" widget="many2many_tags" />
    <field name="email"/>
    <field name="mobile"/>
</group>

6. After the sheet, add the chatter widget (if applicable):

</sheet>
<div class="oe_chatter">
    <field name="message_follower_ids" widget="mail_followers"/>
    <field name="activity_ids" widget="mail_activity"/>
    <field name="message_ids" widget="mail_thread"/>
</div>