I am one of those young fools who is risking trial and error with form. I figure, since I'm not using much weight and have no history of injury, I'm less likely to do something really really bad or irreparable. I can feel within a squat or two if something isn't right. Usually, I need to straighten out my feet or push them a little farther apart. Always, I keep in mind that I am pivoting at my hips. I keep my focus there and think about the force going down through my heels and that prevents me from wobbling or pushing from my knees.