How can I overcome the fear of failure?
You have to know what failure is and what failure can do. Fear is bound to go when you know that failure is not something shameful, damaging, destructive or painful. Feel that failure is something natural. When a child starts to walk, he often stumbles and falls down. But he does not feel that stumbling is a failure. He thinks that it is a natural process to stand up for a moment and then fall again.
If you think of failure in that light, not as something that is against or totally distant from reality but as something that is forming, shaping, molding and becoming reality, then there cannot be any fear. We take failure as something contrary to our expectation and our God-realization. But failure is not contrary to our realization. Failure is something that is urging us towards our realization. What we call failure, in God's Eye, is only an experience.
Always take failure as an experience. Do not take it as a finished product or as the culmination of an experience, but rather as the process of an experience. If you think that failure is the end of your experience, then you are mistaken. In a long race, one may start very slowly, but then gradually he increases his speed and eventually he reaches his goal. If he thinks that since his start was slow, he will not be able to reach the destination, then he is making a deplorable mistake. If there is no failure, naturally you will run the fastest. But if there is failure, take it as an experience that is just beginning. The end will be success. And then who can say that you have failed?