Steady up a bit! Nervousness is quite normal. The set up takes time and if you make a mistake initially that error can compound itself through the rest of the set up procedure and that gets one really flustered. Do not let yourself be hurried. Take the deep breath, relax and go at your own pace. You will be amazed at how quickly the set up comes along. Before you know it you'll have the aircraft ready for the next sector before you are even on blocks after the last.
It does take time to become a complete nimble fingers. Relax, we have all been there. If you are on a really tight turn around, just ask the Captain to do the set up whilst you do the walk around, explaining that he will probably be quicker at it than you. He might well be for the moment but not for long!
