Come at the jump with lots of speed. As your comin up the jump, if you are regular turn to the right of the jump and then before take off, you shouw be turning left, And the other way for goofy. This is done to help you spin as well as stay centered in the landing area. As you are turning left (regular) and just before you take off, spin your arms to the left and turn your head. Keep you area in because it helps you spin much faster. Make sure you turn your head, if you just try to spin your body, you will spin about a 270 and just stop in the air which isnt good. Turn you head and your body will follow. As you leave the jump keep your arms in and keep your head by your left shoulder. After you have spun as 360, you will be able to see the landing. As you are able to see the landing, spot where you want to land and look at that spot. Bring the rest of your body around. To help you spot spinning so you dont spin out on the landing, bring your arms back out and this will decrease the speed of the spin. Extend your knees to absorb the landing. Be sure you are able to land well an switch before you try this trick. As you hit the ground, absorb with your knees and keep looking forward and try to stay switch coming down the landing. If you spin back to regular it doesnt look as clean.

Good luck!