Become a person. You must learn how to think, speak and act. Many people stereotyped thinking or the collective thinking. Try to stand out from the crowd and the confidence will grow in you. Learn to defend his point of view (your opinion) or the ability to insist on.
Know thyself. To defeat the enemy you need to know well. You can't beat fear, not knowing him, not looking him in the eye. Make a journal about yourself and your thoughts, try to be honest with ourselves. Then examine all the thoughts and events of recent days, weeks, maybe you'll see a causal link. And then start thinking positively about yourself, about those changes you want to make in yourself. Think about what prevents you to change or to take a new step, this is a real limitation or are they just invented by you.
Not only think, but act. In addition to positive thinking you need to put it into action. Actions, actually, are key to the development of self-confidence. First you learn to think positively, then your actions change. You are what you do, and so if you change what you are doing, then change what you are.