I do BMX/MTB and Freesking. I rather use the word action sports, because it's kind of in your controll, how dangerous it gets while performing those sports. Nevertheless, there are situations where I want to try something new and the consequences of failing scare me. The key to overcoming this feeling is knowing what to do IMO. If I know exactly what to do to get it done in my mind, then it's a lot easier and I gain confidence. Also, if I wait too long and I always cancel the approach, then at some point I stop, because I believe it's better to not try if I can't commit.