Are you intentionally angling your face each time to the camera? I have always found that buddha smile is the best way to go - the relaxed half smile, just look straight into the camera and imagine you are buddha :) EDIT but I am also absolutely a shameless exhibitionist and have no issues at all about presenting myself to a camera, or a stranger, full on. I know it is not so easy for most people. But I do think you should at least try a couple straight on, relaxed, looking straight into the camera with a half smile and see what happens