Building a smooth and repeatable swing should always be a golfer's first order of business when he starts learning the game. Hitting a ball consistently straight will pay great dividends. But as the golfer picks up the game, he will want to add distance to his attack. In order to do this, he must increase his swing speed.
Practice swinging a weighted club. The weighted club should be about 2 to 3 pounds. The weigh strengthens your wrists, hands and shoulder, and it trains you to allow the club to release, which creates more swing speed.
Get your core muscles involved on the downswing. Again, take a weighted club, but only bring it to the midway point of the backswing, and then shift your weight to begin the downswing. You should feel your cores muscles starting to work and bring the club forward.
Change your overall grip pressure. When you squeeze the club too tightly, you are the club from releasing. Lighten your grip so you can swing the club unencumbered and at full strength. You should hold the club with a grip pressure of about "4" on a scale of 1 to 10. This is equivalent to holding a tube of toothpaste firmly but without squeezing any of the toothpaste out of the tube.
Make sure you have an athletic setup when you address the ball. Your feet should be shoulder length apart. Your knees should be flexed and your body bent at the hips. Your shoulders should be parallel to the target line.
Make a full shoulder turn when you swing your club. This coiling of the upper body will lengthen the swing and give you added swing speed and more power.