Being able to control the cue ball is one of the most fundamental skills that differentiates very good pool or billiards players from good or average players. There are two reasons why this is the case.
First of all, a very good pool player will leave the cue ball in a position on the table that is good for the next shot (in the case that he expects to have another shot) or bad for the next shot (in the case that they wait for their opponent to have the next shot).
Second, a very good pool player will be able to make his cue ball hit the colored ball he is aiming for, where an average player would not in the same situation.
The reason very good pool players can do these things is because they can make white rotate. They can make you spin backward, forward, left, or right, or a combination of these directions (eg, slightly to the right or backward and slightly to the left) with varying degrees of force. They can do this while also making sure you hit your intended target. They can also make sure the cue ball doesn’t spin at all when needed.
What does the twist accomplish? When a spinning cue ball makes contact with another ball, the spin will influence the direction in which the cue ball shoots off the other ball. The target will go in the direction of the turn. Pool players who have mastered this art will use it to determine where the cue ball goes after it has hit the other ball.
For example, a backwards spinning cue ball will roll backwards after hitting the other ball. If it is spinning to the left it will roll to the left after hitting the other ball, to the right it will roll to the right and so on. The amount of spin will determine how far the ball rolls. Therefore, it is possible to leave white anywhere on the table you wish for the next shot, assuming there are no other balls in the way, of course.
Having the cue ball in a good position will obviously make the next shot easier than it would be otherwise. Pool players who have this skill will use it to some degree on almost every shot they play.
The other way that very good pool players can use the spin of the cue ball to their advantage is to make the ball deflect on its way to the flush ball. For example, if there is a ball blocking a straight line between the cue ball and the colored ball they want to hit, they can make the cue ball curve around the blocking ball and still hit the intended target. Weaker pool players would be in this situation and would resort to bouncing off the sides to try and hit the desired ball (or play a different ball).
So how do you spin the cue ball? The trick is to make sure the cue makes contact with the ball off center and in the direction of the intended spin. For example, if you want the ball to spin backwards, have the cue hit the ball directly below the center point. If you want it to turn right, hit it to the right of center and so on. Hitting it above the center point will cause the target to move forward after contact, so follow the colored ball.
It doesn’t have to be too far from the center. Too much off center will cause the cue stick to go off the side of the ball and result in a bad shot. Make sure the tip of the cue is well marked with chalk so that it has a good grip.
Practice makes perfect with this technique. Once he has mastered it, his pool game will improve dramatically. Good luck.