We all have a narrative in our mind that tells us what kind of person we are, what we are capable of achieving and how good we are. No one tells us, but this is the only thing we truly have control over. The way you think about yourself and the kind of person you tell yourself you are is the most important narrative to control.
If you allow negativity and destructive thoughts to dominate your perception of yourself, you will fulfill those thoughts. If you consciously fill your mind with a positive narrative, constructive thoughts and a perception of yourself that empowers you, you will fulfill those thoughts.
Controlling you internal narrative is more important than anything else you can do for helping to make positive change in your life. Make conscious strides every day to improve one thing about the way you perceive about yourself. Learn to control your internal narrative, or it will control you.