Before there is action, there must be setup. Your body must be ready to do what it is you ask. If you contort your body into your "setup", you've already rid yourself of the ability to hit a good shot.
What constitutes a good setup for a typical 7-iron shot?
(the 7-iron is used because it typifies how to hit a wedge through 6. Woods and long irons have setup modifications to be made for maximum accuracy and distance - they do not require a downward blow)
VISUALIZE THE PLANE
You should feel athletic and comfortable. Feel as though you're ready for a ball to be hit to center field. Feet should be just under shoulder-length apart. Wider will encourage hitting fat. Hang your arms to the ground like a monkey. Place the hands on the club, folding them around the club with palms on opposite sides. I could go on about the grip forever. This will be a node of its own.
Many golfers have alignment issues. The best way to eliminate these is to align the ball toward the target. Line the logo up on the tee either perpendicular or parallel to the target line. Then, when you address the ball, place the grooves on the clubface perpendicular or parallel to the logo on the ball. Feet placement is a very personal issue. In general, the back foot should be square to the target line, and the front foot should be slightly open.
For the 7-iron through wedge, the ball should be midway between the ankles. Remember, the ankles. The toes will belie your actual center of stance if your stance is open on the left side. Most people who hit the 7- through wedge fat have the ball too far forward because they're thinking that the ball should be midway between the toes.
This largely depends on what you want to accomplish with the shot. For the typical 7-iron shot, the hands should be ahead of the ball, off the left thigh. This encourages a downward blow, and also eliminates the tendancy to hit fat. One can hit the ball higher or lower by adjusting hand position at address. Higher trajectories do risk fat/thin, but sometimes that's what one must do to score.
The clubhead's optimal plane is that plane formed by the ball and your shoulders at address. Keeping the clubhead on this plane will maximize efficiency and accuracy. Ideally, one will attempt to backswing on this plane as well as downswing on it. This makes achieving a proper top-of-swing position easier.
ALLOW THE CLUBHEAD TO OPEN
This is the meat of the matter. Hold the hands as far from the shoulders as you can. TURN THE SHOULDERS!!! Don't break down the arms by turning them without the shoulders! Imagine that your spine is the axis of rotation. Turn your shoulders around it, keeping the angles formed by your shoulders and arms the same during the swing. I refer to this as "maintaining the triangle". Your right elbow will bend as you do this. Your left elbow will not.
As you turn the shoulders, the clubface will open with respect to the target. This is normal. The angle that the shoulders make with the clubface does not change during the backswing. Most amateurs swing way outside the line (ABOVE the plane-gasp) in an attempt to hold the clubface square. This is futile. Let it open as it should. Cock the wrists in as you swing back. This is not a right/left motion. That constitutes wrist breakdown. Rather, to get the feel of the proper wrist cock, stand at address and bring your thumbs straight back toward your body. The real trick in keeping the clubhead on plane is to synchronize this wrist cock with the shoulder turn.
If you follow these suggestions, you'll arrive at a wonderful top-of swing position, with your hands behind your head. From there, it's simply a matter of smoothly uncoiling. When uncoiling, remember that the power does not come from the arms. The proper first downswing move is to restore the left knee into its preswing position, simultaneously dropping the right arm close to the body. This forces the hips
to start the turn. The hips pull on the shoulders in a torsional
fashion, and the arms, staying out in front of the shoulders, sweep the hands through the swing. Do not consciously uncock the wrists during the downswing. This will happen automagically
if you stay on-plane. The plane outlined earlier represents the energy minimum
for the clubhead to remain on during the downswing, and due to centrifugal force
, requires no energy input
from the hands to correct it. Rest assured that staying on this plane will result in the swing contacting the ball square and hard. For all intents and purposes, ignore the ball. The ball just gets in the way of the swing. Continue applying power by turning the hips and shoulders until the ball is struck. Be sure to keep extended
with respect to the arms. This is the primary reason to avoid up/downward motion of the lower body, and why it is so important to maintain the angle that the spine makes with the ground. Overswinging results in all kind of evil variance
in both of these swing qualities.
At ball impact, you should be in much the same position as at address, with several exceptions. First, the clubhead is moving (duh!). Second, your hips should be open to the target. This is because they're pulling the shoulders through impact. If you involve yourself in pausing the hips at the bottom to maintain them square, you'll be introducing another timing aspect to the swing. I find it's better to maintain the same torsional angle between the hips and shoulders at impact that you had at the top-of-swing. This ensures that you're pulling the rest of the body aggressively through the ball. It also requires an aggressive shift of the body toward the target to maintain this position, which incourages a spinny downward ballstrike. This is usually desirable with 7->wedge.
Note that the shoulders are in the same position at impact as they were at address. This is very important. This is what ensures that the clubface will be square to the target. If the hands didn't do anything evil during the back or downswing (like twist with respect to the shoulders), they must return the clubhead square when the shoulders return to the ball. All this squaring was accomplished by swinging back and through correctly, on-plane.
I believe that Tiger Woods' success is largely due to his ability to keep the clubhead on-plane. Watch him. His top-of-swing is beautiful, and the clubhead is directly on-plane in virtually every normal shot. It's also square with respect to his shoulders at the top of swing. From there, he aggressively turns his hips, pulling the rest of his body in perfect synchronization. The clubhead can't do anything other than return to the ball aggressively and squarely.