This is a question I get asked a lot. Why do my friends hit the ball so far and I don't?
Lets focus on a couple of things.
1. Using your whole body to swing the golf club. I want you to do an experiment. Go the range and throw a couple of balls, only using your arms. Try to keep your body still and do not use your shoulders and hips. Then I want you to throw balls using your whole body. You will see a noticable difference in distance!
2. Tempo. I see most players start their backswing way too fast. If you start so fast you will not be able to complete your backswing. You need to think, Low and Slow. Complete your backswing by turning your shoulders to 90 degrees. This means you will be able to generate more power.
PGA Head Golf Professional