Pretty much never use the front brakes on dirt. It's hard to get used to at first, but it will save your ass.
Also, going downhill, you will learn to love the rear and get used to it sliding around. Once again, awkward @ first, but you get used to it, then you like it
Throttle... well, usually more=better. The throttle is definitely your friend when getting out of a situation, unless you are on rocks, then it's probably not a good idea. I'm talkin' big rocks too, not gravel.
You will also need to learn to stand up and let your legs absorb most of the shock, otherwise your ass will be killing you.