This video explains a method called "exposure therapy." The narrator assumes the scariest thing we can imagine is dying. Just before 02:18 he says we should do things which remind of of dying so we will become accustomed to the fear and it won't scare us as much.
If we can conquer the worst fear, then other fears will not stop us from doing what we need to do.
These other fears are different for everyone. They may be fear of rejecting certain people. They may also be fear of embarrassment, or failure, or a broken heart.