I want to get into LaGuardia High School..?

Hey as far as singing I don't think you have to sing at all. All the advice I can give you is practice. Also it doesn't matter what song you play. Just pick what ever yoour best at. Also you have to be able to read music! Chill out about it though in the middle of the year there will be a apecialized high school conviention, they will be there and give you information on what you need and the requirements. My friend is going there fpr the same thing, she is a freshman. Hope I helped a bit.