PREPARATION is vital to your act; I can't stress this enough. You will already know this I hope; I have learned this the hard way many times over. You'll need to prepare in order to get your act "properly executed" (lower the risk of error.) Everyone knows that there's nothing worse than messing up on stage.
A checklist can make this nightmare of preparation something you can cope with. Once you know you've prepared properly, you can then concentrate solely on your performance; it lets your mind be a little more relaxed, knowing everything is in order.