I can only type this as ground crew on military aircraft, however when learning our "see-off" and "see-in" procedures i found that i would get extremly nervous when the aircrew were approaching the aircraft and when the aircraft returning from a sortie would be approaching the pan.
I found "and it doesnt work for everyone" that if i listened to a certain song or type of music it would relax me enough so that when i went out to do a see-off or see-in i would have a clear head. I also talked to my instructors after each procedure to see what they had picked up on and then concentrated on correcting the mistakes 1 at a time.
hope this helps in some way