Start out mogul skiing. No joke. They teach you how to do crazy good 3s. When I quit moguls at age 13, I was pretty good in the park because I had so much control of my spin.
Anyway, don't listen to people who say wind up.
Get a stacked stance, arms ready, feet about shoulder width apart, athletic bend in the knees. A real strong position so you can pop off the jump. Be patient on the jump, then pop. Once you pop, start looking with your head. Try to keep your head and eyes up because that will keep you in the front seat. Try to get a spot uphill at 180, then just keep going with your head and the spin and get ready for the landing.
Also, try a real jump about 10ft to 15ft.