Well congratz on the acceptance.
Here's what I used to do,I perform on stage often and these techniques always worked for me.First of all,make sure you know the material you are performing like the back of your hand. Always know it before you perform.Take deep breaths before starting. Acting overly-confident always helped me for some reason. Even if your gut is telling that you're totally going to bomb this,give the impression that you have all the confidence in the world,and keep telling yourself that repeatedly. And if it helps at all,close your eyes,pretend that you're just back in your bedroom,singing in front of the mirror like you always do.Good luck!