Choose the Best Possible Shot:
There are a few things you can do to get the most out of your headshot session. The first, and most important is to be sure you choose the absolute best photo from your shoot.
Article: Choose the Best Headshot from Your Session
Crop Your Photos Properly:
The second thing is to make sure that you crop your photos properly (if your images are already shot close, you may not need to crop them). An improperly cropped photo can make your body look much bigger than it is, make your face look small, or even make you off-centered in the frame, which will make you seem lopsided.
Article: Guide to Cropping Your Portraits