The clear can be a high defensive shot and push your opponents to the back of the court to give you time. It can be a flat attacking shot to get the shuttle behind your opponent.
The clear is a shot played from your rear court to your opponents rear court. Top singles player must have super control on the depth and trajectory of the clear and this can be done of loads of practice.
Start with the splits step after your opponent hit the shuttle. Turn and approach the rear court establishing a sideways stunts. Begin to elevate the front arm take the racket back with the racket face downwards using relax forehand grip.
Create a position with the shoulder and Elbow in align with your eyes looking at the front arm. The rear foot is placed well back parallel with the backline with the rear leg loaded. Drive the hips upward and forward making contact with the shuttle above the racket shoulder tightening your grip as you do so.
Also notice the pulling in of the front arm to control the rotation of the body. Land in the wide stunts and the rear foot turn out, see back foot and front foot in quick succession.
Supernation and pronation of the forearm is vital for efficient hitting in badminton. All forehand overheads including the clear involves the supernation of the forearm on the back swing and pronation of the forearm on the forward swing.