In his book The Power of Now, Eckhart Tolle argues that there is but one fear - the fear of death and that fear is a totally unnecessary form of pain.
There is a fear of physical death when we find ourselves in a situation involving physical pain. We also fear dangerous acts, taking physically dangerous risks or being in unsafe places. This is "normal" for most people but is actually pointless. When we find ourselves in danger in the midst of some crisis, there is usually no time to fear. Instead, we do whatever is required to escape the situation. Certainly, fear may prevent us from doing something stupid in the near future, but most stupid things are much more easily avoided through common sense or thought, so fear is unecessary. Fear can only exist when we have time to imagine the possibilities of death in our future, and it is this fear that prevents meaningful action in the present.
What then of social fears? Why do we fear presenting in front of a large audience, or asking someone out on a date? Rejection, we might say, but rejection carries a form of death within. We have social fears because we fear ego death. The ego is the bundle of memories and patterns that we often (falsely) define ourselves by. The ego craves success and sees its death in failure. Failure implies imperfection, that we are not good enough to do something.
Thus, the best way to overcome fear is to understand that we as human beings are already whole within ourselves. Then failure has no consequence and we are free from doubt and worry. If we die to the past every moment, and in doing so destroy the ego which brings only pain, there is no room for fear. (IMHO)