you have to accept the fact that you're going to fall every once in a while but at the same time believe you won't get hurt. once you get comfortable enough, you'll have greater confidence performing the trick and you won't be fearful.
Fear is always there trying a new trick. I was about to piss my pants when I tried a backflip. But I had a bunch of friends to pressure me into it and get my confidence up. (the one place peer pressure is a good thing ha). Then I say to myself "Whether it's today or tomorrow, someday I'm going to do this so I might as well get it over with." Take a deep breath. Concetrate on exactly what you are going to do. Visualize it. Balls to the walls.
ride as much as you can it does go away. and watch lots of ski movies so you see that its all been done b4. But its all just time. It will go away, so enjoy it wile it lasts b4 you become the next crazy kid
Few deep breaths hit my fists together a few times while I visualize the trick and just go.. The longer you sit around the more time your mind has to fuck with you. You just have to let your body do its thing.
This was definitley my main point. DONT WAIT! The longer you wait the worse it gets. Get to the top of the jump/rail/feature your goin to slay, visualize yourself doing the trick perfectly then riding away, then go stomp it! Also, go with a bunch of friends, like the other guy said, peer pressure helps a ton with doing new stuff.