While practice is always better, there is nothing wrong with reading up on the subject.  One of our very own autocrossers, Vivek, not only can wrangle a car with the best of them but he also writes.  He has written some good articles on the how and why of fine cone crushing.  Everyone should take a peek and check it out. http://www.beyondseattime.com/  It’s a good all-around read concerning how to drive an event.