I think there is something, more important than believing: Action! The world is full of dreamers, there aren't enough who will move ahead and begin to take concrete steps to actualize their vision.
The first great advantage is that your subconscious mind begins to work under a universal law: What the mind of man can conceive and believe- the mind can achieve. Because you visualize your intended destination, your subconscious mind is affected by this self-suggestion. It goes to work to help you get there.
When you do the wrong thing, knowing it is wrong, you do so because you haven't developed the habit of effectively controlling or neutralizing strong inner urges that tempt you, or because you have established the wrong habit and don't know how to eliminate them effectively.
Work now becomes fun. You are motivated to pay the price. You budget your time and money. You study, think, and plan. The more you think about your goals, the more enthusiastic you become. And with enthusiasm your desire turns into a burning desire.
Like success, failure is many things to many people. With Positive Mental Attitude, failure is a learning experience, a rung on the ladder, a plateau at which to get your thoughts in order and prepare to try again.