Tempo can be defined as the elapsed time of your golf swing from the moment you begin your takeaway to the completion of your follow-through. Amateurs often struggle with finding the proper tempo because they think they need to swing much faster than they actually do to generate power and distance. But even some golf professionals find that they must slow down their tempo when they fall into the habit of rushing their swings.
Relax when you address the ball. Tension is a major cause of a hurried swing tempo. Be deliberate with all the actions you take prior to taking your stance and setting the club behind the ball. Walk up to your ball slowly. Take relaxed, easy practice swings.
Check your grip for signs of tension. In his book "Golf My Way" Jack Nicklaus recommends holding the club lightly at address, then firming the grip slightly before you begin the swing. The goal is to find the amount of grip pressure you need to maintain control of the club without tensing your hands and forearms, which can cause you to jerk the club back rather than starting smoothly.
Use a slow, smooth takeaway to set up the proper tempo for the entire swing. On the practice range, experiment with starting your swing much more slowly than you normally do and see if that improves your overall tempo.
Complete your backswing. An indicator of a hurried swing tempo is not taking the club back as far as you can while still maintaining balance. Not only do you lose potential power by shortening your swing arc, you're also likely to rush the club down from the top, robbing your swing of both power and accuracy. Have a playing partner watch you to see if you're fully finishing the backswing.
Start the transition to the downswing deliberately. You don't need to stop at the top of your swing, just make sure you don't pull the club down quickly with your hands. Begin the downswing at the same pace you completed the backswing, not faster. The instruction book "Master Strokes" recommends a mental image of setting the clubhead on an imaginary pillow for a moment at the top of the swing.