The same principles apply to the kill shot as to any other drive. The major difference is the angle of the racquet face in the delivery and impact. The racquet face comes down through the ball causing the ball to hit the front wall with spin. This then makes the kick down towards the floor and sidewall, ideally hitting the nick. To play this shot successfully you generally need a good angle of attack. In clip 1 the ball comes off the back wall to the centre of the court. In clip 2 the ball comes off the side wall into the centre of the court. A common fault with the kill is that players try and burst the ball. Yes, you do need to hit the ball harder than a normal shot, but always maintain control over the racquet head. I played against Brett Martin on numerous occasions and was always mesmerised by his ability to kill the ball. As you can see from clip 2, I did pick up a few tips!
Kill 1
Kill 2