It's all just practice. I can pop a quick 180 without setting an edge, but I've been riding for a while.
The thing that helped me learn them was to do front 1's on whatever bump, mogul, etc. I could find as I was just riding down the hill. Become a little human tornado. The repetition will help you learn the muscle memory needed, as well as becoming comfortable landing on your switch heel edge. You'll get more comfortable with it, and then you progress onto bigger jumps, spins, or whatever.