Hi Steve, Ok so there are a few technical points that can really help keep the short touches low over the net. Firstly when you step in to the table for the touch it’s vital to stay low and also keep your head and body close tot he ball to avoid losing control. If you reach in to far and contact the ball away from the body it will tend to pop up high and easy for your opponent to attack.
Also with the timing point on the short touch, if you take the ball too late it will usually mean it goes higher as well, so try to take the ball early, imagine the feeling of almost a half volley where as soon as the ball has bounced you are looking to come in early and contact with a quick sharp brush under the ball.
Check if any of those points might be happening when you are doing your short touches and let us know if that helps!