The quickest way to gain Self-Confidence is to do exactly what you are afraid to do.
Sometimes while writing, I feel like I do not have enough words to tell what I would like to tell. But then I just start writing and something starts coming on its own. So I believe in the thought. If you are afraid of trying something then do try it. Something good will definitely come out of it. If everything else goes to worst at the least you will have the experience to share.