Tips on improving self esteem?

Hi everyone,

So, like the title says, I'm looking for any tips or tricks for improving my self image. I have dysthimia, and I've pretty much had low self esteem for as long as I can remember.

It's really affected my dating life and career goals, because anytime someone shows interest, or a new opportunity arises I think "I'm too fat, ugly, stupid, etc." And shy away.

I know I'm overweight, and I have a few scars and moles and what have you, but my friends and family have told me that shouldn't matter. Logically, I know they're telling the truth (and not just to be nice), but in reality I hardly ever leave my house lest someone see me and think I'm ugly. I'm a 25 year old grad student, but I feel like a terrified teenager at a high school dance!