Recovering
If you are tipping backwards, then drive in reverse. This levels you out and vice versa.
When coming off a really high jump and you cannot see any ground, lean backwards slightly to about a 45 degree angle. This can usually stop you from tipping over forwards into a hill upon landing.
If your truck is on its back, press both [Down] + [Right] or [Up] + [Left]. This will help you to get back on your wheels, but do not go too far.
Steep hills
When there is a steep cliff edge, get your front wheel over and the 4WD will do the rest.
Speed down steep hills. Usually there will be a large hill in front of you that you will need to jump over.