>>1
Make her like her body and her looks. Not by compliments (though that might be a very good combo), but by making her get good use of it, and feeling pleased about what she can do. Join martial arts classes with her, or something. The gym could be one option, but too many feel that the strength/agility you gain there is too separated from the outside world (due to it being a bit more difficult, especially for chicks, to "impress" others with how much they can handle in the gym, rather than just by looks - which is rather shallow).

Pick up some kind of hobby with her, or make her pick one by herself. Perhaps judo, yoga, or.. urgh, "pilates" I think it's called? Akido, karate or kung fu or "rougher" arts might be good for her as well.
The idea is to get her to be proud over what she can achieve with her body. Meditation probably would be useful as well. If she can get peace of mind, she ought to be able to like herself more, and to accept compliments.

Compliment her in unusual yet flattering ways. Focus on complimenting aspects she has more control over, and things she does, rather than things she might be afraid of losing (thus feeling it's a very volatile state, and disliking being reminded of that she will have so much to lose). Another good thing is to rather than going "nice [something]!", put that quality of hers in relation to you, as well. "I love the way your lips feel against mine." or "I love getting to see your gorgeous eyes when you're happy to see me". Make the compliments a part of you, rather than just loose words of appriciation that could have come from anyone.