After knowing your stock, the second thing you may do is to appreciate and give proper value on all your attributes. Remember that each of us is a unique being which is perfectly fit to for uniqueness. We only have to be careful of identifying our unique spots and in the process, help them shine from us. Perhaps you live under cold critical eyes that know nothing of imperfection. Or maybe you are the underling of a brother who achieves in school, thus the intense focus on him and frequent disregard for you. Probably people do things for you when they feel like you cant do things on your own. These are subtle triggering instances that would all contribute to your eventual loss of self confidence. There is no such world but because men tend not to listen to the voices that encourage them to believe in themselves, this world came forth to life. The thing though is that experience and time are often good teachers, if we truly take them as such. We will live with ourselves for as long as we live with them. They are for real and they will actually dig deep in your subconscious mind, which will then be integrated into your being. If you believe in these then there is no way that you won't believe in their direct opposite. Central to building self confidence is one's belief in himself. Whatever you set your mind to believe will all be taken as factual. It will create proofs of how unable and incapacitated you are against shining. It will make you believe in time that you truly are worthless and insignificant. It would store memories of such failures to be recovered when you falter with "unbelief". This inner critic will eat you up until it overpowers your sense of self. However, doing the best don't necessarily mean that they qualify to the universal standard of being the best. In fact, there are so many cases when their bests may have been a mediocre standard for others and in some cases, their best is no good at all. Nonetheless, they still perform them because they know nothing better.