I know I do this when I am writing something. I pick someone, and it doesn't necessarily have to be someone I know, and model my characters after them. Just looks, not personality, ideals, convictions, etc. I try to collect photos of the person which, thanks to the internet, is really easy if I am imagining a well-known person. Different expressions, different clothing, etc. Was just curious if anyone else in these parts did a similar thing.