Speed and Carom control are two essential elements of position play and is very important in a game like nine ball that is heavily position play dependent.
Speed control is making the CB travel as far as you want it but not too far. It takes practice and patience. One method of practice is to set up a shot and place a piece of paper on the table in the path of the CB and try to make it stop on the paper. Do it till you get reasonable with that shot then change the angle of the hit and do the same. That is a good drill but I get tired of drills after a couple of minutes. Another way to get a lot of practice is to play smart. When playing do not just think i want to get down over there somewhere but pick an ideal spot and try to get to it then watch your results. If you never think of a spot to land the CB you will not pay much attention to the resulting speed and your progress on speed control will be very slow. If you deliberately shoot for speed and pay attention to the result during regular games it will help a great deal in learning speed.
The same is true with CB carom, very important in position play. If you want to learn the angle the CB will travel after hitting the OB, predict the angle / location on cushion the CB will go after it hits the OB then watch it and see how close you were. Keep doing that and you will get good at it, which is essential for position play. If we just concern ourselves with watching the OB go down the hole we will be missing half the game and not progress. It is important to watch the CB after the stroke to learn advanced play.
