Headshots are as personal and customizable as people themselves.
Things to think about when getting a headshot:
Where will the photo be used? (billboard, posters, business cards, email signature, etc
Do you want to incorporate your branding? (props, colors, tones, etc)
Are there restrictions for 'what is allowed' for your headshot? (some companies only allow neutral backgrounds or not allow outdoor photos)
How can you best represent yourself in your headshot? (do you normally wear a suit or jacket, do you want a white collar or blue color style, studio / backdrop or lifestyle / outdoor?