Look into the mirror for a bit, and just come to terms with who you are. So maybe your hair doesn't look as straight as you want it, look at it in another perspective, its got curls, its got bounce, its got flair. And maybe your stomach isn't so thin looking, but you've got a nice body in general, and it looks in proportion. Start to come to terms with what you do and don't like, and accept the flaws, and embrace your beauty. When you're working on something, look at how you're doing things differently, and tell yourself, see I'm doing it THIS way because then blah blah blah, and you start to feel smarter and more confident. You can always compliment your friend for things she does 'perfectly', but you've got your own things to. Just don't be too strict, because you can't get perfect, it only looks that way from someone else's point of view.

As for your social phobia, I think once you get more confident with yourself, you can try mingle a bit. It's okay if you're silent, but lend someone an ear, and they'll be happy to talk to you. And you can then input some of your own opinions, and strike a conversation. I have a social phobia myself, maybe not too bad, but I get nervous very very easily. I can't perform or public speak, if more than three people are watching me do something, I'll get very very nervous and just mess up. I can sometimes find awkward silences unnerving, and will start blabbering. So don't worry, i know exactly how you feel.