For the record...Backs aren't easier than threes (many people can do a 3 just skiing down the hill. Haven't seen any backs that way yet...), but they aren't as difficult as many people think.
For those of you looking to try them, try to get some practice on a trampoline or diving board before taking them to the snow. That will help a lot. On the snow, it's about commitment and timing. Choose a jump that has quite a bit of pop and preferably a soft landing. You don't need to go huge. As you pop off the lip, throw your head back, like you're trying to look at your tails. (I would throw your arms up and back as well if it is your first, just to make sure you get around.) From there, just look for your landing and it should come around. The big thing is dont' chicken out or you'll get stuck upside down. COMMIT! As for controling your rotation, it is based on how hard you throw and how tight you are in the air. If you tuck, you'll spin fast. If you lay it out, it will be slow. Those are the basics...