How do you deal with self doubt and failure?

It is good to be afraid to fail, it means you care and it will make you push yourself further because of it. When I get the feeling that I might not be extremely confident at something, I never allow myself to not do it, because that sets a mental precedent where you will allow yourself to quit spontaneously. It sounds too simple but sometimes you just need to put one foot in front of the other and get the job done even if it is not perfect.