There are a few very important rules to adhere to when posing for a head-shot.
Know your brand and look.
Wear what you normally wear..that’s your uniform, avoid bulky clothes.
Make sure you are well groomed and and your clothing is clean and pressed.
Use the right expression, it’s your goal to look likeable and professional.
Showing some teeth is usually best but not compulsory if you don’t want to, but a slight smile is good.
Props are generally a no no.
Avoid selfies and your photos have a lifespan of 1-2 years only.
A white background is better than a cluttered outdoor one.