At a strategic level, American Pool is all about gaining and retaining control over the table. Whenever your opponent has the play, there is an opportunity for him to clear his object balls and pot the 8-ball to win. To succeed, you must carefully plan your shots in an attempt to clear the table without fouling or losing control of it. The skill therefore, is in understanding the angles to not only guide the object balls into the pocket, but to place the cue ball where you want it for your next shot.
Regardless of how many balls are potted, following a break the table remains open – see American Pool Rules. This means that the existing or incoming player must call and pot an object ball in order to claim its group. For this reason, one of the crucial elements of 8-ball strategy is being able to scan the table during open play to determine which group would be favourable. In practice, this means indentifying easy and problem balls. A typical easy ball is any ball that is so close to a pocket that it could not be easily knocked into the middle of the table without being potted. A trouble ball is any ball that cannot be easily potted or moved from its existing position without a high risk of fouling. With experience, you can expect to become more adept at identifying which group is the more favourable group. By electing to target the favourable group, you give yourself a better overall chance of success in the game.
During play, you should continually review and analyse the table to identify opportunities or potential pitfalls. Often it is necessary to plan how to address a problem ball by planning a few shots ahead. In addition, it may also be prudent to plan ahead to minimise risk when you stand to lose control of the table. For example, a player may often find himself in a scenario where he cannot realistically expect to make a legal pot to retain control of the table. Often, it would be preferential to make a legal shot that leaves an opponent with a difficult subsequent shot than to attempt a difficult pot that could easily result in a foul.
To facilitate shot planning, a player must develop a keen understanding of angles and how spin can alter the path of the cue ball, both before and after contact with other balls. When attempting to pot a ball, always try to imagine a straight line from the centre of the target pocket running through the centre of the object ball. Wherever that line exits the back of the ball is where contact should be made. Regardless of which angle the cue ball approaches the object ball from; it should follow that path if contact is made at that point. To visualise this, players often imagine a ghost ball touching the object ball at the target contact point. To make a successful shot, a player need simply aim the centre of the cue ball at the centre of the ghost ball.
By making make wise group selection choices and planning shots carefully, you have much of the strategy element covered; the rest will come with experience. As you play, you will learn the finer points of spin control and how to use power to determine the finishing position of the cue ball. For beginners, it is important to visualise the desired path of the object ball, the subsequent position of the ghost ball and to aim the cue ball for the centre of the ghost ball.