The headshot has to be in color. Black and white images are outdated.
You should look like yourself on a regular weekday.
Keep your make up and styling to a minimum so it doesn't call attention to itself.
The picture shouldn't be cropped too tight. It's okay to crop the head at the top slightly but some of the torso should be visible.
Your headshot should be taken at eye level to create an honest and undistorted look.
Keep your hands away from your face. Your face should be the "star" and nothing else.
8x10 is the industry standard size for headshots (preferably portrait orientation).
Staple your resume on the back of your headshot in all four corners (back to back).
Your headshot can have a border or it can be full bleed, it doesn't matter.
You should look confident and inviting.