We all strive to become better at who we are, at what we do. Or we should try. Some know what to do in order to get there. But don't realise it.
Every time you have an intent of doing something you think is right, a voice inside stops you. And that's your voice; you are your greatest enemy.
To overcome yourself you must know yourself. "Not everything that is faced can be changed, but nothing can be changed until it is faced." - James Baldwin.
So face yourself, find out who you truly are and who you want to become. And make a conscious effort to transform who you want to be into who you are.