I agree that it's not a good idea to use cribsheets so I use them sparingly. I find it helps if I write down the titles of the songs I know I can perform well AND THE KEY I SING THEM IN. For some reason, when I'm on stage I often draw a blank about what key to start in and that's one that's very hard to cover up. If I start it out right that's half the battle, right there. And yes it's amazing how songs that you sing perfectly at home/in the car/shower etc. - can fly out of your mind when you're on stage!