Best way to stop chain bouncing..?

Hey, on my mountain bike I'm having some problems with my chain rattling around and making some really horrible noises when jumping off dirt ramps and park bench's... I was wondering the best way to stop this happening? As a little preventative Ive been putting the gearing into the biggest chain-set on the front and cog on the back but it still bounces around... What's the best way to solve this? Could i somehow tighten up the derailleur? Remove some links from the chain? Thanks...