Essentially, if you're curving to the left, start on the righthand side of the road (obviously), but as you go through the curve, guide the car to the lefthand stripe. Coming out of the curve, move back over to to the right as you straighten out.
What you're really doing is spreading out the force required to turn the car. Think about it in terms of Mike Tyson. Would you rather have Tyson punch you in the chest once, or have a 100lb weight rested on your chest for 15 seconds? The total force exerted on your chest is similar; but speaking for myself, I'll take the latter, thanks.