In 1969, Bruce Lee took out a piece of paper and wrote himself a letter:

My Definite Chief Aim I, Bruce Lee, will be the first highest paid Oriental super star in the United States. In return I will give the most exciting performances and render the best of quality in the capacity of an actor. Starting 1970 I will achieve world fame and from then onward till the end of 1980 I will have in my possession $10,000,000. I will live the way I please and achieve inner harmony and happiness.
Bruce Lee
Jan. 1969
Bruce Lee had only 4 years to achieve his goal. And that’s exactly what he did! Bruce had a definite purpose and achieved everything he said he would. Although, from his letter, we can conclude that it is overflowing with 1 personality trait. And that is CONFIDENCE! But where does it all come from?
To build confidence and succeed, you need to have a definite purpose. You need to know what you want more than anything else, why you want it, how you going to get it and when you want it. This thought then becomes the dominating thought in your conscience. Someone once said: “It is better to work on each goal individually. Achieving your goals is like carrying eggs in a basket. Put all your eggs in one basket because carrying too many baskets breaks the most eggs.”
Always think big and aim high! This leads to bigger achievements. And this is where confidence comes in. Confidence is believing in yourself and believing that you have the ability to succeed. A lack of confidence does not mean that you will not be successful or achieve your goals. It only means that you will become shy, scared, fearful and often miss opportunities. Once you have confidence, you will be able to achieve almost anything. This unlocks new opportunities, new adventures. 
Oprah Winfrey once said:
“It is confidence in our bodies, minds, and spirits that allows us to keep looking for new adventures.”
So gain the confidence, turn your “I can’ts” into “I cans” and start making the impossible possible!