The driver may be the most important club in the bag--of 18 tee shots per round, the majority require a driver. Hitting long and straight drives will set up even the most challenging par 5s and help keep your score low. One important factor in driving the ball well is beginning with a good stance.
Your feet should be shoulder-width apart. Your feet should be straight and aligned parallel to the ball's intended flight. The placement of your feet and the ball will help you get lift and power. Iron and pitching wedge stances require that your feet be closer together.
The ball should be placed a few inches inside the instep of your front foot (left for right-handed drivers). The ball should be close enough to you so your arms can hang comfortably but not so close that you can't extend them.
You can measure your stance by standing in front of a mirror and placing a yardstick in front of your feet with your feet closed. By moving your feet apart in 3-inch intervals, you can find three foot stances, including the driver stance, which is the widest--shoulder width--with the ball forward. You should bend your knees to stay balanced.
Your back should be straight but slightly angled at the hips to allow you to comfortably reach the ball with your club face. You don't want to hunch over the ball, which will likely lead to a mis-hit because you'll be too close to the ball to extend your arms and take a full swing.
Situate your legs to balance out your backswing, downswing and follow-through. If you use a wide, shoulder-width stance, you will be more effective in sweeping the ball while maintaining balance. The driver should come through the ball easily during the downswing and follow-through.