I agree with Artchic, it's really difficult to change the entire person. It would be far better seeing a therapist to process your feelings. If you're set on that though, you could make a list of everything you want to change, pick the smallest change and come up with solutions for that change. Rinse and repeat so to speak. Good luck. You may find that if you dislike yourself now, that baggage may still be there once you change.