I say get someone who is PSIA trained if you take classes. There are plenty of dynamite skiers out there. Few can put into words what your body should be doing in the turn like a professional teacher. The best can watch your form and tell you exactly what you are doing wrong or right. Worth the money in my book, and you take one one hour session then work a few weeks on it, come back for more when you have digested the MANY little nuances. Or just go skiing a lot. If you get some bad habits in the muscle memory though, they can be virtually impossible to remove. Ask any tennis instructor.