They are twins. They are the flip side of a coin. As you build up your belief in yourself to do something you gain the nerve to do it. Once you do it or attempt to do it you start to notice what you are doing right, that it wasn’t as bad as you had imagined it, and that maybe next time will be even better.
As you feel more competent at the activity you start to believe more in your ability to improve and maybe even get good at it. This gives you more confidence, even if it is mostly visualization at the beginning. So I could go on with this email but I think you can see my point. The confidence leads to taking more chances and doing things better, so that increases competence, and the increased competence increases your confidence. It will radiate out of you.
Dale Carnegie said it best: Do the thing that you are afraid of. That is the one sure way of conquering your fear! (He was talking about public speaking, but it can be related to many things).
Until next time!