Believe it or not it is actually easier to do a trick than it is to do straight airs. It is easier to stay balanced in the air if you are thinking about doing the trick and the motion of the trick will keep you on axis/from stop flailing around.
Work on a 360. That is the first trick you should learn before you start trying grabs and all that other stuff. Or you could try the following:
Double twister daffy
All are great mogul tricks that when you throw them in the park all the snowboarders and kids laugh at you. I enjoy the reaction from the old school mogul tricks more than anything.
Try doing the helicopter than when you are at 180 and your back is to the judge throw the spread eagle and then finish your rotation.
Another GREAT trick to learn is a helicopter with a rewind. Throw the copter and when you come all the way around keep your skis moving in the same direction and then rewind them back before you land (just do a twister after the copter)
All very good stuff.