The leg with which you hit the ball, make sure that it is slightly bent and the ankle is locked, as if you hit the ball with a tip. The whole movement is to hold the leg and the ankle and hit the ball in the head.
As you approach the ball, concentrate on keeping your shoulders and head away from the ball to keep your shot on target. Run towards the ball and take 3-4 long steps by putting your non-kicking foot on the ball and pointing your toes towards the target.