Depends on what kind of stage fright these people are dealing with. Best you can do is visualize the audience as a whole, instead of every individual. I haven't performed in front of crowd that much (doubt anyone here has), though the few times that I did I thrived under the pressure. You just shift into another gear and try to leave them in awe. Controlling your levels of noradrenaline is detrimental, though it might be very hard to some due to genetic and environmental factors. Keep in mind that anxiety can be partly inherited. Some tackle this issue on a whim while others have to dig deep. Now, being spectated in a game is easy. Just perceive them as bots, ezpz.