Post Shoot is just as critical as the photo shoot itself. There are various steps to consider when choosing your photo's before you use them in your business promotions.
First consider where the pictures will be appearing. Different media may require different sizing options. For instance, in Facebook and Linkedin, if you use your new photo as your profile pic, you will need to consider that the image must be square. If you add your picture, consider if it will end up cropping your head and shoulders. Select an image that allows a great "square" cropping opportunity. How else will you use your images and what shape (square, rectangle, vertical/horizontal, etc) will be used in that type of media.
Are you a hands in pockets or a folded arms kind of person? Use the headshot to establish your brand for flyers and other advertising.
Ensure your photographer gives you high-resolution versions of your headshot.
Consider taking an environmental portrait along with your headshot.
Get a second (and third) opinion. It is tough to objectively pick the best images from the proofs. We can be our own worst enemy. Also consider what image makes you feel confident in yourself and then along with other selections, get a second, third, and fourth opinion. It's like taking a poll, where you get great feedback. Listen to the feedback.