We have the ability to choose, we are God's higher form of creation, we surpass all other forms of life and we don't use the mental faculties we've been given. We don't even understand what we are capable of doing. School doesn't teach us anything about ourselves. So the more we learn about ourselves, the more we take control over our life.
You've got to develop mental strength. And you develop mental strength with the will. The will is the mental faculty that gives you the ability to hold one idea under the screen of your mind to the exclusion of all outside distractions.