There are so many things you can do. It's pretty much entirely up to you as to what you want to put in there. Remember no tangs that have the same body shape go together, damsels are mean, Wrasses jump, mandarins need pods to eat, and don't overstock your tank.
Make your rocks so they have little caves and hiding places and plenty of swim through areas for fish when they are stressed. Don't buy cheap non-name brand stuff, that stuff usually fails and failures in this hobby get very costly very quick.
And take lots of pictures