For some this is a difficult kick to apply power to but it is an essential technique for the taekwondo skillset. The hook kick can prove to be a great asset when striking a high target such as someone’s head! Many opponents will mistake the beginning of a hook kick for that of another kick such as roundhouse and a skilled practitioner can switch many other techniques into a hook kick on the fly in order to score. Variations include starting from the rear leg as described here, the front leg or spinning before striking with the rear leg. For devastating impact use the back of the heel to strike and for lite contact sparring extend your foot forward to slap with the toes.
Here are the basic steps of the Rear Leg Hook Kick laid out in a horizontal fashion as a quick reference guide. You may get the poster size of this by clicking on the picture.
Now that you have the basic steps, you must practice them and refine your technique. Get those motor skills programmed in and fine tune the mechanics. As I said before, I would work with an instructor on the details because there are a lot of details in between each step and far beyond the scope of this guide.