you can honestly pull 3's off of anything, even rollers. Some tips:-Dont wind your arms (very bad habbit and scrubby)-Turn your shoulders and look over your shoulder (everyone says it, but its very true)-Dont be scared trying it on a big jump, if you can rotate it but are having trouble w/ the landing, you usually arent spinning hard enough to have a bad crash; usually just a washout-Stay calm. Keep your arms under control, but dont be surprised if one goes up to keep your balance. What i do is I spin left, and saftey grab my right ski to keep my body from flayling-Practice them on small shit like rollers n stuff just working on turning your shoulders n shit
Its honestly all about practice. Keep at it though. Once you get them down, they're (in my opinion) the most fun trick because its nice and smooth and easy to learn grabs with.