I think of what I value in my friends and family, and then remind myself that I have a lot of the same qualities. Things like honesty, compassion, loyalty, a sense of humour, and a desire to help others. When I get down on how I look in a mirror, I remember how much more I have to offer. On the days I like the way I look, I'm happy that the outside is starting to match the inside.
Another game I like to play is to find something beautiful about everyone I see. I play it on the bus: sometimes it's something they're wearing, or a nice smile, or how gracefully they move. It helps me do the same when I look at myself, and is a good reminder that beauty is everywhere, not just magazines and on TV.