Driver

One can say that the driver is the second most important club in your bag -next to your putter. A good drive sets the tone for the rest of the hole. Will you be scrabbling just to get back on the fairway, hoping for pars and bogeys, or would you prefer going for the green and birdies? By gaining a few extra yards from such drives, the subsequent iron shot will be that much easier, as will your chips, putts, etc.

1. Body Coil
Tiger Woods and other great golfers generate tremendous power by ‘coiling’ their upper body with a big shoulder turn. The hips, however, don't turn to the same degree. This creates tension and torque, not unlike a rubber band being stretched before it lets fly. Try to keep the right leg and knee bent, but rigid, as you draw the club away and fully rotate your shoulders. On the down-swing, unwind and rotate through the ball with your hips. Your navel should be facing the target at the end of the swing to ensure a full turn.
2. Develop a "Lag"
Successful drivers all have a "lag" in their swing. On the down-swing, the wrists must release their energy at some point and the point at which this happens is key. The closer to impact with the ball, the more stored power there will be. Many golfers deliver this source of power near the top of the swing or early on the way down and end up swinging with arms only on contact. This is commonly called "casting" and is the opposite of lag. One drill for improving this is to cock your wrists at the top of the back-swing, forming a right angle between your arm and club. Pull the club down in slow motion while doing your best to retain this angle. Try to incorporate this into your full swings and remember to release those wrists through the ball!
3. Swing with the Entire Body
Some of the biggest muscles in your body are the upper legs and trunk and you should use them to put power into your swing. On the down-swing, your legs should begin the drive and the trunk begins the turn, ensuring that the bigger muscles have much less chance to ‘twitch’ under pressure than the smaller ones. This is why good swingers seem to move effortlessly as their small muscles are led by the larger ones. Try it!
4. Left Arm Straight at the Top
Make sure your left arm is kept relatively straight on the back-swing to ensure a wide arc. Keep some distance between the hands at the top of the swing and your shoulders and head. This produces more club-head speed without swinging any harder. Davis Love III and Vijay Singh are great exponents of this. Watch them!