When golf pros are waiting around during a tournament, I see a lot of them staying loose by just swinging the club with their left arm. Should we focus more on using the left side to swing the club and less on the right side?

Drills should be specific to each individual. Drills, like the left arm swing drill, are for those who hit too much with the right hand. However, I’ve noticed that most students are too upper body powerful and when they learn to effectively use the ground is when they improve the most.