My daughter is now 12 and is adorable.
She was just the same from as young as i can remember she had poor self esteam. She found it very difficult to make friends because she was so grumpy and always wanted her own way. Therefore she really didn't like herself. She often wished she were dead, or said she was just too ugly. It was quite draining! I often blaimed myself thinking i must have done something. Her school was no help either, they had problems with her not being nice or not joining in. They blaimed me for working (although i worked part time when she was at scool anyway).
She changed gradually from starting the junior school. I sent her to a different school to her peers. This school didn't let her behave the way she was used to. She also made a different set of friends who hadn't seen her be so awful (I believe she reacted some ways because the other children and teachers expected her to) I also continued telling her how good she was now that she was growing up. Everyday I slipped in comments about how beautiful she looked. She also needed to be told "yes you are clever and you can do it".
She was at an age where we could have one to one girlie days, although she still doesn't like shopping for very long. She often gets too attatched to girls when they become friends, but she is getting better at being her own person. She is now very confident and likes herself. She never says anything negative about herself anymore.
Hope this helps!

Worthy Praise(when they do something good), and loving praise(when you just feel you love them and want to compliment) given them when appropiate by picking up on cues from your child. I meant to reply to original post btw oops
GleninHull