My main ball flight mistake is a push-slice. Video analysis shows that I pull the club too much inside and then swing just slightly over the top on the downswing and with the club face open slightly (or even maybe opening because of the motion). It's easy to see when the blur of the club is cutting across the ball. Try it as a drill or notice your practice swing.
The easiest way to swing the club without effort is to simply let gravity do it for you with maybe a little assistance to get some "oomph!" How? From the top of the backswing, simply drop the club and arms while the back is still turned, while simultaneously rotating the left hip backwards. This will stop the over the top move and result in a nice, relaxed, languid swing. The body will naturally react to this falling motion to prevent the arms from crashing into the body; Shawn Clement is a big proponent of this, as are many other teaching professionals.
The feeling I have is that I lift my arms straight up in front of my chest while turning fully (back facing the target), get to the top, and then drop my arms and hands while my back is still turned while also immediately rotating the left hip targetwards and backwards (again, the back is still turned); from there everything just happens automatically. This creates a tremendous "X factor," where the hips are open while the shoulders are still mostly closed (an X shape is formed due to the difference between the hips and shoulders). There's no flipping of the wrists; the left forearm turns so that the back of the left hand is flat and "slapping a wall" or "closing a gate." The pivot is driving the motion as the club "falls"--closing the club face while also approaching the ball from the inside. The blur of the club face feels flatter to the ground and appears more circular (less linear), such that the blur approaches the ball from the left-rear (the inside).
Two additional important points: The grip should be slightly loose but firm enough to rotate the club. AND turning the shoulders a full 90 degrees (back to target) will allow for an easier inside move.
This move gets the right elbow in front of the right hip coming down, a key position seen in almost every professional.
Another way this feel has been described is "swinging to right field." This is a baseball analogy (that isn't exactly true) but it ingrains the feel of a proper inside-out downswing.
This reverse looping action--often called "dropping the hands into the slot"--is taught by Hank Haney and many other professionals, including Bradley Hughes. But in reality, it's a classic way of swinging that has fallen out of favor with todays upright swingers. Ben Hogan made this two-plane approach famous.
Here's Bradley Hughes on Hogan's swing:
It's easy to see from Hughes' analysis of Hogan's swing that Hogan did a lot of great things, including keeping the club and arms in front of his body all the way through. He also used his pivot to square the club face rather than relying on an artificial rolling of the forearms. Keep in mind that Hogan fought a hook, whereas most of us fight slices; therefore, an overly active lower body is a great way for hookers to straighten out their shots and even start hitting fades, which is what Hogan did using the torque of his lower body. Slicers (like me), however, need more active arms and less body (hence…drop the arms while turning the left hip back). Too much lower body motion for a slicer will only make a slice worse (Haney).
Most amateurs try to help the club toward the ball by pulling on it from the top of the swing. They are, in effect, trying to help gravity—one of the greatest forces in the world. Mother Nature doesn’t need your help. She’ll get it done—if you don’t pull on the club.
When you’re at the top of the backswing in good balance, you literally let (key word even if it’s small) your arms drop through space as you turn your hips left and get your weight onto your left heel at the completion of what’s a lateral turn.
[From Golf Tips - The Fire Drill]
Wherever your eyes are looking, your hands and the clubhead will want to go. If your eyes are looking at the back of the ball at address, then you are probably trying to square the clubface to the back of the ball at impact. Address and impact are two very different alignments in golf. Focus your eyes on the inside quadrant of the ball at address and your hands will strive to reach your new focal point. By making this small change, you will be well on your way to improving your downswing and obtaining much more manageable misses.
[From Classic Swing Golf School]
Upon reaching the top of the backswing, simply allow the arms to fall vertically. The shoulders must be relaxed and the arms must feel light. This motion is dependent upon gravity, as well as, the golfer permitting the arms to drop from the top. This will allow the club to fall in the slot. With this technique, the golfer must resist the urge to work the club out to the ball. The outward action of the clubhead results from body rotation, therefore, the arms must fall from the top of the backswing before any rotation of the body begins.
[From Classic Swing Golf School]
Butch and I [Tiger Woods] worked hard on my first move down--letting my arms fall as my weight transfers to the left, and keeping the club more in front of my chest instead of behind me. When you see me make that little drop move with an air club, it's a reminder of that first move down. The lesson for you: Start the downswing by letting your arms drop as your weight shifts targetward.
From the top of the swing, the arms and hands are passive, essentially in free fall. As the club lowers to waist height, the feeling is that the right elbow drops in and the left arm is extended.
"The farther you line up left of your target, the farther you'll hit it to the right. With that being said, you've almost got to feel like you're swinging toward right field and putting some hook spin on your ball." ~Zach Johnson, PGA Touring Pro