When my daughter was a small person, we used to get her into the mood for being photographed by showing her a camera and saying 'There's a pretty girl in there' Luckily, the majority printed were just that - a pretty girl. Examples are hanging on her walls as we speak. She has a new person now to make her look pretty. I reckon he is lucky like me - all that was needed was to press the button. She did the rest.
Mind you, it is in the genes of course!