While the emphasis of this video is taking the ball on the rise, it does raise one of my favorite points- prepare high and swing straight through the ball. A common mistake I see is preparing low (as if you are going to hit at a normal ball at hip height) and then swinging very loopy to get from that low starting position to a ball at your head height. This gives you no margin for error (a millisecond slow/early, and you are framing the shot). Also, this stroke gives you no power since you are almost entirely brushing and not contacting the ball. By preparing high and swinging level, you have a much better margin for error and power, and the ball will drop into the court due to gravity. You don't need to swing that hard (no kill shots), but your ball will be fast and flat - very tough for the moonballer.