Instructions
Listen to the photographer's instructions as he poses you for the first set of photos to be taken. The photographer will likely pose you in a way where your shoulders will be turned at a 45 degree angle away from the camera and your head will be turned toward the camera with your chin slightly raised. Once in this position you can make changes that will make shooting the headshots easier on the photographer.
Change your facial expression. Whether you start with a smile or straight face, change your facial expression only after each picture has been taken. This will give you a number of different images from which to choose.
Change the position of your hands from resting in your lap to crossing your arms, to bringing one hand up to the side of your face to rest your head on. You can also position your hand just under your chin. Just like the facial expressions, these small changes will alter the look of each picture.