How to help someone feel better about themselves?

Get her to listen to Bob Marley & 2pac. Yes, I'm being serious. I was similar then I got depressed bla bla bla. Started to listen to them and suddenly I learnt to f**k em all! If someone does'nt like you for who you are, don't like them. Show you don't care what they think! Tell her they all think the same but put on a brave face like she should!

I say the same but with Oasis.
And also, try and make her see what it is that makes her special, and better than those people she compares herself to...

No!! Definately Pac and Bob <3 They changed my life

Well, Oasis changed mine! And that's actually an euphemism.

Listen here, you! I'm tired I can't see how it's a euphamism! Please explain xD

haha what I meant is that saying they've changed my life is not enough for what they have done to me... do you know what I mean? I'm tired too

You have to try and demonstrate it to her I guess. If compliments don't work because she thinks you're trying to make her feel better, maybe get a male friend to talk to her / go out with her and tell him not to be afraid of complimenting her?

In my experience, the most successful way to go about trying to boost someone's self-esteem is to give them empirical evidence that is not easily refuted (if at all refutable). Also just let them know you're there for them and do small gestures and make little comments. They might dismiss it initially and maybe even always but over time, I've seen this have a small impact