Advanced player looking to add more width on their backswing and improve their left arm position should try this neat little drill from Vijay and put a headcover under their right arm
A common fault in the set up is having your head down and chin too close to your chest, this drill will fix that and allow you to turn effectively and use your legs correctly in the swing
Although you might not know it you have the ability to control the distance on each of your clubs, use the numbers game to figure out how long you should make your backswing to hit each club whatever distance you want