How do I kick (Kickboxing/MMA)?

Start practicing on the heavy bag. Practice kicking as hard as u can and with speed. Each time u kick that bag it in prints that into ur bone on your legs. If u do it with less effort or sloppy. Then that's what it will in print into ur bone and u will not do as good. Expect only the best out of your self and keep repeating these exercises everyday. Practice strength and speed. As long as u practice that, i promise u will get better.