Your ability to create power comes from your lower body. If you are lacking power in your golf swing, it could be from a faulty weight shift. Using only arms in your golf swing, restricts your power and causes a variety of mis-hits. Learning to shift your weight is key to adding power into your swing. Try this exercise is to help build a powerful weight shift.

Stand with your feet together.
Hop laterally onto your right foot.
Immediately change directions and hop laterally to the left foot.
Continue hoping side to side without stopping.
The key is to hop and land lightly on your feet. Get some air under your feet.
Repeat for 8 to 16 repetitions alternating side to side. To make it more challenging, hop both feet together.