Good choices and ideas already given. Let me add my support. Counter each negative when you catch it. If you say I hate myself, say "No I don't hate myself, but sometimes I do things I hate." That might work instead of a more positive, "I like myself."

You can check out Dr Clay's book, via the self help forum. He has stuff on how to do this.

I agree that even though telling yourself the truth (the positive) might feel like telling a lie, but keep at it, it does reach the brain and changes your thinking in the long run