Pretty young to be a principal, must be a fukked up school, but good luck to him.
My advice is to identify immediately, the teachers who actually care, even if some of them might be a bit unorthodox, and work with them. And also try to get to know the kids, and all of them, not just the obvious good ones. Try to reach those kids, who have potential, but for whatever aren't living up to it.
And most importantly don't let the politics(which he's gonna have to deal with a lot) get in the way of his main job. Which is to help bring out the best in them kids.