Many golfers think the words "tempo" and "rhythm" are synonymous, but they aren't. Tempo means the pace of your swing--how fast or slow it is. Rhythm describes the order in which the parts of your swing move.
One golfer can have a fast tempo, like Rickie Fowler, and another can have a slow tempo, like Ernie Els, yet they can have the same rhythm, or sequence of movement.
In my view, rhythm is more important. I've seen many successful golfers with fast tempos and many with slow tempos, but I've seen very few with poor rhythm. Good rhythm sets up the transition, or the way the club is set at the top before moving into the downswing. Those with good sequencing--virtually all tour players, including Jason Day (above)--start down with the feet. The hands and arms react to the movement of the feet, knees and hips. The club gets left behind if you start down with only the chest and upper body.
To get a better sense of how the different parts of the body should move in rhythm, consider how far the clubhead needs to travel in a golf swing: about 18 feet from the top to the ball. The hands move about six feet, and the hips just a few inches. So players who fight a slice might need to feel as if they release the club earlier with the arms and hands. That encourages the clubhead to catch up to the body so the face is square at impact. Players who battle a hook might need to feel the club lagging more, with the hands and arms leading the clubhead through impact.
Work on your rhythm, and your natural tempo will emerge. You'll hit better shots with more consistency.
Jim Flick, a longtime Golf Digest Teaching Professional and PGA Golf Professional Hall of Famer, worked with hundreds of amateurs and tour players including Jack Nicklaus.