You don’t have to be a professional model. We work with people every day who have varying degrees of comfort in front of the camera. To make yourself comfortable, practice in front of a mirror. Bring some ideas to the shoot in the form of expressions and looks that you want to try. You can even bring photos from favorite magazines that contain elements of what you’d like to see.
The best thing you can do to improve your headshot is to get a full night of sleep the night before. An extra hour wouldn’t be a bad idea. Drink lots of water so that your skin is hydrated. It’s a good idea to stay away from alcohol or other substances the day before your session. If possible, don’t drink coffee or smoke just before the shoot.