LearnToPlayPool.com
The Mechanics of Playing Pool
by BCA Certified Instructor Chris O'Donnell
Taking a Stance - Balance, Comfort & Consistency
Copyright 2003-2010 Chris O'Donnell All Rights Reserved
A good stance uses the entire body to support the cue as you stroke. Because people come in different sizes, your physical characteristics will dictate the positioning that works best for you. Although this means that no two players stand exactly alike, there are some universal objectives that make playing pool a lot easier, and that good players have in common. These include balance, comfort and consistency.
Distribute your weight evenly on both feet for better balance, and position your feet far enough apart to bend over comfortably. Balance and comfort make it easier to get your chin down as low as possible, preferably no higher than ten inches or so above the cue. It also helps avoid the use of unnecessary muscles which helps tune out distractions so you can focus on shooting the shot. Finally, it helps you stay down in your stance, without raising your head at all, until the stroke is completed.

Feet well apart with weight evenly distributed,
straight lead arm, chin low over cue
A consistent stance requires consistent foot positioning. The position of your feet should let you to face the shot squarely while holding the cue on the target line. Point your lead foot somewhere between 20 and 30 degrees inward so you can keep your balance and still face the shot. Point your back foot outward 30 to 45 degrees. This pivots your shoulder and hip outward to create room for your grip to clear your hip as you stroke. Many different foot positions will get the job done. Experimentation will help you determine what works best.
Stand the correct distance from the cue ball. This distance is determined by the location of your back foot. It should allow you to fully extend of your lead arm and keep your head far enough back for good aiming. Standing too close to the cue ball makes it much harder for your eyes to judge angles and distances. Standing too far away, on the other hand, puts too much strain on the muscles in your legs, with a negative effect on your concentration and stroke.
Good distance also helps to keep your shooting arm (elbow and upper arm) directly above the cue the entire stroke. Think of a swing plane, which is like a pane of glass that splits the cue down the center from tip to butt. The swing plane should also split your shooting arm in half. Keeping your lead arm straight and your shooting arm directly over the cue fully extends your upper body, preventing your grip from teetering side to side outside the swing plane as you stroke. This promotes a pendulum-like motion which helps keep the cue on the target line the entire stroke.
A pendulum swings from a fixed point. A common example is the pendulum in a grandfather clock, which swings from a hinge. During the stroke, your forearm and grip swing like the pendulum in the clock, with your elbow serving as the hinge. In order to keep your elbow fixed (not moving up and down as you stroke), it helps to keep your elbow as high as, or higher than, your shoulder. If you're having trouble getting your elbow up high enough, try moving your stance (i.e. your back foot) a little further back.
When bending over into your stance, bend from the hips, not the waist. This lets your head drop down without moving too far forward as you bend over. Once down in your stance, if you realize the cue is significantly out of alignment, don't attempt to realign the cue without getting up and repositioning your feet. Because the alignment of the cue is dictated, in part, by the position of your feet and hips, it will prabably return to the same incorrect target line as you stoke, defeating your effort. When this happens, get up and reposition your feet.
Once you find a stance you like, you can REVERSE ENGINEER it so you can take the same stance every time. First, without moving your back foot, stand up slowly, moving your front foot back until your heels are a few inches apart. Second, place your grip against the front of your hip with the cue tip on the cloth pointing at the center of the cue ball. Now observe: (1) the distance between the cue tip and the cue ball, and (2) the location of your back foot in relation to your grip.
Take a mental picture of both and burn them into your memory. Then, whenever you take your stance, just grip the cue as usual and place the cue tip on the cloth the memorized distance behind the cue ball. Next, without moving the cue, move into position with your grip against the front of your hip, placing your back foot in the memorized location (in relation to your grip). Once your back foot is in the correct position, you can move your lead foot into position, then bend down into your stance.
Work this approach to taking your stance into a pre-shot routine. A good pre-shot routine is like a built-in reminder of how to take the same stance every time. It can be performed in less than five seconds and increases your confidence. By keeping your mind focused on the positive steps required to get into the correct position to execute the shot, you leave no room for negativity to enter into the picture. There is no substitute for the power of positive thinking.
Many shots require an improvised stance. When the cue ball is more than three feet away from the cushion in the direction you need to shoot, your forward hip and leg run into the table, preventing you from reaching the shot. This occurs at the ends of the table, and from the sides when the shot has you standing at an angle. On such shots, do whatever it takes to get your upper body fully extended on the swing plane. The rules allow your to play from any positon as long as you maintain continuous contact between one foot and the floor while shooting.
Occasionally, you must raise or "jack up" the butt of the cue. For example, when shooting over an object ball blocking the back of the cue ball that is close to the rail. You may need to move your feet closer together. Before narrowing your stance, however, you may find you can go up on the toes of your back foot a bit in order to raise your upper body. You may even find the heel of your front foot coming up slightly off the floor to get the cue where it needs to be. As long as your are comfortable enough to maintain your balance to execute the shot, this can work quite well.
Good luck!