Well,the most important thing in the golf swing to me, is the movement of the lower body from the top of the swing.
First off, you start down below with your knees and your hips.
At the top of your swing, you move the lower part of your body.
Not your shoulders, the lower part of your body.
Letting your arms and hands follow.
Bringing you into position to hit.
But this is the first movement, there.
Then you release at the bottom.
Most people do it entirely opposite.
They rotate their shoulders first, instead of their lower body.
As a result, they come across the ball and hit the outside of the ball,
instead of the back of it.