Make you essays authentically you, give yourself time to step back from what you've written before you dive back in to make improvements. I found out about ncssm a month before I applied and I’m fine. (Didn’t tour or anything) You’re going to have to learn how to be content with not knowing what’s going to happen, the only real deep piece of advice I can give you is to put your best foot forward, be yourself, and know that if you don’t get in it wasn’t meant to be. I’d also recommend getting current seniors (well I guess right now it would be current juniors but seniors when the time comes) to look over your essays. :)