Picture a quarterback throwing downfield: The longer the pass, the farther back he pulls his arm before throwing. The same is true in golf: To hit it long, you must stretch your arms away from the target in the backswing, creating a wide arc.
Also like a quarterback, you need to start from a solid foundation. A wide base lets you create extension while staying balanced. Then you must have the courage to make a full stretch away from the ball. The following setup adjustments -- and drill -- will help.
Build a Pyramid
With your driver, set up so the insides of your heels are under the outsides of your shoulders, forming a pyramid from head to toe. Play the ball opposite your front heel and tilt your spine to the right so the club leans slightly away from the target.
This wide setup gives you the stability you'll need to reach back without losing your balance. It also helps you engage the large muscles of your arms and chest to push the club away. The forward ball position delays the club's release, keeping your wrists hinged until just before impact.Drill: Reach Back
Place your driver on the ground, straight back from your right foot, and put a chair at the other end. Pick up the club and swing back slowly, trying to nip the chair as you pass it. If the clubhead clears the chair, you're not getting enough extension. If you move the chair on the way back, you're overreaching. A perfect extension just grazes it. Once you've extended to the chair, you've completed your shift to your right side.