I've always practiced infront of a mirror until I can perform the trick without looking at my hands. As Mr. Book said, your nervousness will go away the more comfortable you are with presenting the effect. What I did to get over nerves when I started was show my friends and family first since I was close to them and didn't feel like I was judged. Also, when you want to present to a stranger, I always bring a buddy with me to catch it on camera. (Reason 1: It's an excuse to have company with you while you do magic, Reason 2: I can watch the video later, see what I did right and what I did wrong). I think everyone is nervous at first but it's like riding a rollercoaster. At first you're nervous, when you're on the ride your heart races, but by the end of it you realized you enjoyed it. Next time, count to five and throw yourself on the ride. Less thinking more doing!