How to give form to kicks?

Hi!



I have more than 10 years of practice (which is somewhat irregular) in martial arts. I have always assumed my kicks to be rather good.



However, my teacher told me that my kicks were not effective enough to subdue an opponent. I was quite surprised to hear this. I admit that maybe I have to work on my hips to make my kicks more quick but he also told me to give form to my kicks.



I know that I used to train with pads and punching bag to make my kicks more effective. But does anyone knows how to give form to kicks?