|#1 - Swing your arms and club back in one motion (the one piece takeaway). You can practice this by placing a ball on the tee and hitting 7 iron shots with a 1/2 swing. Your arms and club should swing back to waist high all in one piece - then follow through all in one piece to waist high.
#2 - Cock your wrists in an upward fashion. On the human body, wrists are wonderful parts that move in many different directions. For a good golf swing, they should cock in an upward fashion. Hold your club directly in front of you and cock your wrists up until they reach a 90 degree angle. Go back to the swing drill from step #1 and add the wrist cocking up. This should make your swing about shoulder high with the wrists at a 90 degree angle. Practice 3/4 shots with the swing going shoulder high to shoulder high on the follow through - still off a tee with a 7 iron.
#3 - Turn the body. Similar to a baseball pitcher when throwing, the body should turn away from the target on the backswing and towards the target on the follow through. Continue your swing drill now adding your body rotation for a full swing.
In conclusion, your three steps to a better swing would sound like this, 1) swing the arms and club together, 2) cock the wrists a little more upward, 3) turn the body back and through the swing.