1. COVER THE BALL
The biggest mistake I see with amateurs is, they hit off their right foot. To make a good iron strike, you must hit down on the ball. The only way to do that is to get your weight left. Push hard off your right side. A good feel is that you're "covering the ball" with your chest at impact (1).
2. SHAKE HANDS
The whole right side of your body should turn to the target. Shift left, and extend your right arm. A great image is that you're shaking hands with the target (2). Or picture a shortstop turning a double play: He steps on the bag, and fires his right side to first base.
3. DON'T THINK LEFT
I hear teachers saying to swing left through impact, really get the club tracking inside (3). That might be what happens, but a better thought is to swing straight down the line. Swing to your target. As long as your arms don't fly off your body, the club will go left. Plus, most golfers already cut across the ball; why would they want to try to swing to the left?
BUTCH HARMON, a Golf Digest Teaching Professional, runs the Butch Harmon School of Golf at Rio Secco, in Henderson, Nev.