One of the core concepts I focus on when teaching my students is simplicity within the swing and the importance of impact. The most common errors I see as an instructor is the ball slicing to the right (for a right-handed golfer).This happens mostly when the face at impact is open. This can be produced in many ways.
There are many variations to the golf swing. Just take a look at the best golfers of all time: Jack, Johnny Miller, Mr. Hogan, Arnold Palmer, and Sam Sneed. All swung the club differently shaping the ball differently, but all are great at impact.
We know now that the face of the club contributes to 85% of what the ball does.
Every swing has a certain amount of up and down and a certain amount of around because we stand to the side of the ball.
Error correction is based on this thinking. If you are too steep, or too narrow, too wide and shallow; the ball flight will tell us. It is my job to pick elements of the swing to make the appropriate corrections.
For most of my student’s, I believe that moving the club on one plane is the most repeatable and easiest to implement.
Meaning the club, left arm and shoulders align at the top. The body drives swing.