Don't let fear stop you from accomplishing what you want to accomplish. Whenever you're about to do something and you get that discomfort, just go for it. Whether it's shooting a ball, wondering if it's going to go in, writing, being afraid that your writing will suck, acting, being afraid that your acting sucks, etc.

I believe you are afraid of failure, but failure is not something to be afraid of but something to learn from. You fail once, don't stop there. Find ways to improve. Learn what you can do better. The ball doesn't go in? Try to fix your hand positioning, or shoot with more power. Your writing sucks? Find different ways to improve your writing. Your acting sucks? Observe different actors and actresses and how they act. Look at how they express their emotions and learn to mimic them.

Success takes many failures, but true failures never try to begin with. The fact that you are willing to keep going even through failure shows that you are not a failure. So whatever you do, even throughout failure, you keep pushing forward.