Every golfer strives for a 300 + yard drive. To explain how to hit it far I am going to turn to the reining world long drive champion, Jamie Sadlowski, whose personal long drive is 445 yards. To put it in perspective, Im happy with a drive of 280 yards. The most surprising thing about Sadlowski is that he is only 5'11 and 165 lbs.
In order to hit it far the most important thing is to create lag between the club head and your hands (the picture below is a prime example) Theoretically the most lag you could create (for a right handed golfer) would cause you to hit your right shoulder. In order to create lag it is imperative that the golfer initiate the downswing with a lower body rotation. This is the most difficult thing for an amateur golfer to grasp. The downswing is not started with a swinging of the hands but with a rotation of the lower body. This cause the club head to lag behind the hand creating lag which equals power.