I learned them three weeks ago, and since then I have put about 30+ to my feet on a variety of different size and style jumps. They are super easy once you get the hang of it.
1. Make sure you have enough speed. A lot of the time when learning inverts I find that I slow down on the inrun too much because I am focused on the trick. Don't do this.
2. When you flip, try and go right over the front of your tips, and not off to the side. You should think about loading your tips a little, like your buttering.
3. Keep your body tucked. Even if you under rotate, you'll still probably land on your skis, but keep tucked up anyway. You don't have to throw particularly hard on anything over about 10 feet. My buddy who taught me explained it like running and doing a front flip into a pool. You don't really huck it, you just kinda lean over your tips and flip.
I think they are actually easier than backies, but that's just me.