It's golf's equivalent of a voodoo curse. You're sailing along in the middle of a decent round. You stand over a routine short-iron approach shot-making what feels to be a normal swing-when ball and hosel meet and the shot careens sideways. More troubling than the ensuing double bogey is realizing that now that you've hit the dreaded shank, more may be in store.
Straight Back, Rotate Through
A shank occurs when you deliver the clubhead outside the ball at impact and strike the ball off the club's hosel. The most common causes are a clubhead moving outside the target line and a lead arm that fails to rotate through impact. Two shank-stopping keys: Swing the clubhead into the ball from inside the target line, and rotate your lead arm so the back of your hand faces the target at impact.

Lay a head cover just outside your intended swing path, parallel to the target line and slightly behind the ball. Start the club back parallel to the head cover for the first foot. In the downswing, try to swing the clubhead toward the ball without touching the head cover. Through impact, consciously rotate your lead arm in a counter-clockwise fashion so that you square up the clubface at impact. You might hit some shots to the right of the target at first, but I guarantee they won't be shanks.