Private Lessons From Golf Magazine

HIGH HANDICAPPER: Get a Grip on Your Takeaway
Many golfers abruptly snatch the club away at the start of the takeaway, cupping their left wrist. This lifting action creates a number of different problems, most notably a narrowing of your swing's arc and an open clubface. To maximize your power, you need to swing the club back on a slower, wider arc, so that your left wrist remains firm and doesn't break down.

To prevent this early wrist break, focus on moving the butt end of the grip away from the target for the first foot or so of your backswing. Don't worry about anything else but the grip. This move will slow your backswing tempo down and also prevent your left wrist from cupping, thus keeping the clubhead on plane and the clubface square.