It's a complex question with a lot of possible answers. But here is some good advice: practice giving. Give something of yourself, preferably to someone or something who really needs it. Volunteer at a hospital, a zoo, a youth volunteer force for the police department, the Red Cross, the city. Be a pair of helping hands, a listening ear, a kind voice. Offer your strength and energy and intelligence where they can really do some good.
Something that will take you outside of yourself while at the same time letting you see how valuable you can be to others--and how beautiful you are to them--will make much more of a difference than you can possibly imagine.