It is said that all things are possible when you believe.
In my view, belief is the factor that outweighs all others when we talk about what it takes to succeed. Many teachers throughout the ages have taught that important life principle.
Think about it for a moment. You may think that you are determined, you may think that you are focused and maybe you are both of those things. You may even be telling yourself that you are committed to success. But do you believe that your success is possible? If you don't really believe it, that lack of belief is eventually going to sabotage all of your efforts even if you keep telling yourself that you are committed, focused, determined and so on. So ask yourself one simple question...do I believe?
Now belief can be cultivated. If your attitude is "I can do it" then reinforcing that maxim in your mind over and over will, eventually, sink down into your subconscious mind and, like learning to ride a bicycle, your believe in yourself and your success will propel you toward the success that you desire.