ericm979 posted the first 5 minutes of auto racing school, and it gets more comlicated from there. Knowing the correct line for every different corner is the name of the traction game.

Of course, psychology plays a part as well. You have to be confident that you know how much your tires are going to grip given your inputs. Recent crashes only make you less confident and more nervous, which makes you tight and twitchy. Luckily, you're not a pro. Sometimes I like to remind myself of that and just enjoy cruising around the corners. I probably lose less than a second with each curve, but it's a more liberating feeling.