During your address position you should notice how your left arm (for the right-handed golfer) is straight out and reaching for the ball…
Maintaining that same positioning at impact is absolutely crucial for a solid ball strike. Any amount of lifting or bending of that left arm will greatly increase your chances of topping the golf ball. See the video below:
Video Summary
Start by making some smooth slow practice swings, only taking the club to chest height on your follow through. At this height, ensure that both arms remain straight (pictures 4 & 5).- Repeat this exercise until it feels natural to maintain that straight arm follow position, and then start clipping the ball from a tee peg without any real power, again checking your follow through arm position. Gradually, as you gain more confidence, increase your power but always maintaining straight arms past chest height.