This tip is from ark Crossfield, GA Golf Coach
Golf instruction for all levels which will help you play some better golf and lower your scores.
In order to achieve a powerful swing which delivers the clubface at the correct angle to the ball it is important that your body coils. A great exercise to help you achieve this can be done with a piece of coloured tape. Stick the tape onto your left chest (right chest if you are left handed).
Place your hands behind your back and assume a normal golf shot posture, with your waste as the centre of the coil, move your right chest across so the sticker aligns itself with your right knee (if you are left handed then it will be your left knee).
This movement is the coil you are trying to achieve, note that it is very different from the lateral movement you see in many amateur golfers. Repeat this movement until it becomes natural.
This exercise can put strain on your back so make sure you warm up first.