I think you’re already doing well. I think it needs to be a combination of trying to improve ourselves and accepting ourselves for who we are. Accept the things you can’t change, change the things you can, but be happy with yourself. That’s easier said than done but I try.

"I want to improve myself and make myself a more positive person", or "I want to improve myself and become a more positive person" Note: Adding 'more' is better as without it, it sounds a little too self-critical.