I might be the shyest person ever. In the world. Ever. But when I cheer I'm the opposite!
I always made a big point to look at the judges the entire routine, and make big facials at them. It seems totally weird- but they'll smile back at you and it just gives you so much more energy!
My coach always said to "Sell it!" you really have to look like you're having fun. When you practice, try to put a facial to each movement, like it's part of the choreography. Every run-through at practice should have full on facials, to get you in the habit!
If you're self conscious of looking at people look at the wall in front of you! That will help you keep your face to the crowd at all times, but won't let you focus on your judges/coach/fans.
If you have an alternate who sits out at practice or someone who's hurt and just watching practice, look at them and kind of make a game out of it! When I was hurt, I sat out and watched every practice/comp. My friends were on the mat cheering, and we'd look at each other and make the biggest facials back and forth, which actually helped them a lot!
Just have fun with it!! Facials are a part of cheering, and the more you do, the better you will look!!