The key for most golfers to improve their game is to improve the consistency of their golf shots. One of the best ways to improve your consistency is to ensure that you start your downswing in a consistent fashion and therefore the timing and tempo at the top of your backswing is crucial to what happens to the golf ball.
As you wind up and create power in your backswing, your body is coiling and creating power and is ready to unleash the power in the downswing.
However, the start of the downswing must be a controlled, connected and consistent movement. Any part of your body that rushes ahead from the top of the backswing would cause a disconnected, out of control and inconsistent downswing and impact position.
A great way of ensuring a smooth connected downswing is to initiate a small pause at the top of your backswing. This may only be for a split second but it allows the body to work in a connected fashion during the downside. Many of the world's best players have incorporated a pause into the top of the backswing, often it is so slight that it is almost impossible to see with the naked eye but it allows the golfers to feel very connected and consistent even under the most intense pressure.
To incorporate your pause, start by taking a short club and making some half backswings. At the top of your swing count to 3 before you make your downswing. This will feel like a huge pause but it sets the tone of making a backswing and downswing as two separate movements without any jump and lurch from the top. As this drill becomes more ingrained, you can lessen the pause until it feels like a momentary pause before you start your downswing.
Work on this to see if it helps you improve your consistency and timing.