jump, try a trick, crash and jump again untill you master the trick in question
Then jump try another trick, crash,...
Make sure that your warming up is sufficient, prevents injuries
Make sure that you keep your balance while airborne
Don't doubt, do the trick you planned to do, do anything else and you have little chance to land
Take a deep breath before skiing to the kicker, helps to relax
Try using a trampoline to get confortable in the air
Hit the trampoline with ski's (tape the edges to protect the tramp, CAUTION: don't use good ski's it ruins the flex)
Hit the tramp while holding your poles to practise grabs
(tape the tip of your poles to protect the tramp)
Get a good insurance policy...
Get to know the nice people at the Emergency Room (to get treated better and faster) *winks*
Use a backprotector and helmet
Wrist guards may come in handy as well