Believe that you can be a lot more of who you already are

Get a pen and paper and write down, “I can be a lot more of who I already am.”
This is far better than believing you can be anything you want to be.

Say what you’ve written aloud.
Keep saying it until you are fully convinced of it.

Post the note where you can always see it.
Use it as a reminder to focus more on your strengths instead of your flaws and weaknesses.