You should never try to change yourself because god made you the way you are and he loves you just the way you are and made every individual beautiful and real friends like you the way you are. Try to wake up every morning and say I'm beautiful I the way I am even if you don't believe it you eventually will. You are gods masterpiece
It is very easy.... starting tomorrow morning, be the person you want to be. You have a fresh start to be anything or anyway you want to be. If you act as if you are that person you want to be..... soon, you will be that person!
Try new things, new people, new place. Be the real you. You are probably hang around people who peer pressure you. Believe it or not there are some really good friends out there btw I understand what you are going threw
Go to the library and browse through the self-help books. There's usually a section just for those. Then look at the subjects. There could be help on feeling more confident, how not to be shy, learning social graces, how to small talk, etc etc. so whatever you don't like about yourself, you can learn how to improve. Everyone has room for improvement. I wish I could bite my tongue more often instead of blurting something out that makes my husband mad.
Sometimes its who we hangout with that makes our personality. If were with our family sometimes we will feel more comfortable with them more than anyone else. With friends it depends on how close you are. Some friends who your close with you will be more yourself rather than those you just met and our still getting to know.