One of the best tips to hitting efficient powerful shots is to keep the club head lagging behind your hands in your forward swing down through the ball. The longer you maintain this lag, the more velocity you can produce and the farther the ball will go when you do release the club through impact.
How is lag created and then maintained? Think of your left arm as one lever and the shaft as another. In your backswing, hinge your left wrist to create at least a 90° angle between the forearm and shaft. When you swing down, retain that angle for as long as you can. When you release it, the club head will speed up.
Many recreational players let go of the lag too early by unhinging their wrists to soon in the downswing. One drill to prevent this is to swing back with your left arm only, and as you start down, grab the shaft with your right hand and resist the unhinging of your left wrist. Repeat this feeling and incorporate it into your swing. In your regular swing, your wrists unhinge naturally at the bottom of the arc.