don't try to show HER you've changed. Change for yourself. There is always room to grow and you have to make growing an ongoing process. Once you start changing for yourself, you will not focus on her as much, life will get better.
Take the focus off her and onto yourself. Are you happy with yourself? What changes to you would YOU like to make? Make a list and work on it. As I said, take the focus off her, focus on yourself. And believe me, she will notice you and your changes. Do not worry about being anything to her, just let flap in the wind...