With the driver, golfers have such an instinct to smash the ball, they sometimes forget about getting in position so they can. Short, fast backswings with no windup lead to weak downswings. You can't hit the ball with power if you don't set it up going back.
Let's look at three checkpoints in this photo. First, notice how much my upper body has rotated. You hear people say, "Turn the left shoulder behind the ball," but the problem with that is, each shoulder has a range of motion independent of body turn. I can move my left shoulder back 20 to 30 degrees without turning my chest. So instead, focus on getting your back to the target—that makes the shoulders and hips rotate to maximize torque.
Second, check out my wrist set. Hinging the wrists creates a very powerful lever in the swing that you can use to create a burst of speed through impact. The angle between my left forearm and the shaft is about 45 degrees here. I have a ton of potential energy to unload as I start my forward motion toward the ball.
Third, I've clearly gotten lighter on my lead leg during the backswing. Think of any powerful throwing motion, like a football pass or baseball pitch: The front foot often comes off the ground, with the weight going to the back heel. That comes from the hips and shoulders turning fully. From there, you can drive forward and apply all the power you've stored on the way back.