I found this article on Golf DIgest.com where Butch Harmon give his “greatest driving lesson“.  It is actually a series of lessons and an interesting read.

I would say that this was the best lesson from the article (but that’s just my opinion):

LONG HOLES: HIT IT BETTER, NOT HARDER

…First, realize that the best way to turn speed into distance is to hit the ball with the middle of the clubface—and that comes from staying in control. Be deliberate on the backswing; give yourself time to wind up before you start down. Your instinct might be to go harder from the top, but that’ll cause you to waste your speed too soon. Make your downswing from the ground up: Shift your lower body toward the target, keeping your shoulders turned, and let the club fall to the inside. Then you can accelerate through and get the distance you need.

Emphasis added is mine.

Be sure to read the whole article as it includes tips related to Greg Norman, Dustin Johnson, Rickie Fowler and Gary Woodland.