Movement. To kick, raise the knee quickly, keeping the leg inward toward center line to protect the groin. Keep the guard up and avoid hunching the shoulders or allowing elbows to move away from the body.
Re-chamber immediately to maintain balance. Keep your center of mass over the support foot. Power comes from the thrusting action, not from a forward movement of the center of mass. The thrusting action possesses a great deal of momentum and tends to pull the body after it, causing a forced forward step, so retract the kicking foot quickly into a stable state of balance. If you must step forward, step outside the opponent's lead foot so you will not be vulnerable to a foot sweep.
The kicking motion may begin by lifting the kicking foot with the sole parallel to the floor or by raising the heel first and then springing the foot upward off the ball of the foot. The springing action is quicker but the correct foot shape is not attained until later in the kicking motion.
Kick snap/thrust forward from the knee, so knee must be chamber to a height so that the thigh points at the intended target.
The support foot may remain stationary or twist into the kick. The kick is more powerful without the twist but the twist adds range and presents less of the body as a target. To increase range and power, allow your supporting foot to be dragged forward by the force of the kicking action. When kicking a heavier opponent, this forward movement resists the recoil from the impact more effectively than would kicking from a rigid stance.