Stance is the most variable fundamental. The anatomy of every individual is unique enough that what works for one individual may not be ideal, or even achievable for another. An individual who is obese will need a lot more clearance around their torso, and female players will require varying amounts of clearance around their chest. Individuals with lower back pain or those with knee issues will need to find something unique to fit their unique needs as well. Since it is nearly impossible to assign a one size fits all solution to stance, I will explain each of the core concepts of what a fundamentally sound stance will achieve, balance, clearance, visual alignment, and comfort.
A Solid Foundation
Stance is quite literally the foundation of your game. In order to achieve a consistently accurate stroke, you need to be balanced. The stability a good stance provides will prevent any swaying of the body that would inevitably result in a less than reliable deliver of your cue. The general guidelines to achieve stability and balance is to have your feet spread at least 1 shoulder width apart and off set from one another, meaning your non shooting foot should be farther from the shot line than the heel of your shooting foot. Lastly, try to distribute your weight evenly between both legs.
Clearance
The amount of clearance needed will vary for each person. What is important is to establish unhampered movement of the cue. Too little clearance and your chest or torso will get in the way of your stroke. Try to give your stroke too much clearance, and you will be stretching back over to the shot line to try and see down the line which will throw you off balance. Something else to consider is that your grip hand, forearm, upper arm, and shoulder all need to be aligned along the shot line.
If you step too far over the shot line, your shoulder will also be too far over the shot line and vice versa. In either scenario, your arm or wrist will have to bend and twist to get to a position where your hand is able to hold the cue back over the shot line, or you will be stretching so much that you will be unstable. When you stroke it will be crooked and difficult to deliver the cue accurately and consistently.
A general rule to follow to achieve enough clearance without putting your body too far over or away from the shot line is to place the toes of your shooting foot up to the shot line. In addition to the placement of your foot, locking out the knee of your back leg will provide additional clearance. Obese player may have to lock out there back leg to get the additional clearance it provides. The main takeaway here is that you need your entire right arm from your shoulder to your grip hand to be aligned over the shot line and to be able to move the cue freely back and forth unobstructed by any other part of your body.
Visual Alignment
Visual Alignment is important because you need to be able to see down the line that you plan to shoot the cue ball. Most players place their chin directly above the cue, but some players may place the cue slightly to the left or right of the middle of their chin if they are significantly eye dominant on one side. The height at which you keep your head above the cue is quite personal and really comes down to personal preference, but it is worth noting that every modern top class pro keeps their head very low and near the cue. What is most important is that there should be no head movement (up, down, or side to side)at any point while shooting.
Comfort
Comfort is important when finding the right stance. If you are uncomfortable, you may find yourself rushing to get up off of the shot which is generally bad for your game. That being said, comfort should not be an argument for keeping your old stance that does not meet the three criteria above. Make small adjustments to the recommended stance that I will provide below until you find something that is generally comfortable, causes you no pain, and which meets all three of the criteria above.
General Guidelines for How to Form Your Stance
Applying the general guidelines from above, this is how you should set up to start finding your individual stance. Line the toes of your shooting foot up to the shot line. Your foot should be pointing anywhere from 45 - 90 degrees to the shot line. Avoid pointing your foot away from the table, which would be anything above 90 degrees. Additionally, don't point your shooting foot parallel to the shot line. Step out with your non-shooting foot by at least 1 shoulder width and point that foot in the same general direction of the shot line. Lastly, ensure that your non-shooting foot is further away from the shot line than the heel of your shooting foot.
Feel free to take a larger step out, just make sure that your weight is close to evenly distributed. You can lock out both of your legs, slightly bend just your front knee, or slightly bend both of your knees. Go with whatever is more stable, more comfortable, gives you enough clearance, and provides you better visual alignment. The typical pool stance has the non shooting foot stepping out about 45 degrees to the shot line, but snooker players will commonly step out a bid wider to square up to the table. Go with whatever feels better to you. Just ensure that entire grip arm, chin, center of vision, and bridge hand are lined up along the shot line and that there are no obstructions to your stroke.
My (Jake's) Stance
I personally start with the toes of my right foot on the shot line with my head and eyes straight above my toes looking down the shot line. My right foot is around 70 degrees to the shot line. To start out, the majority of my weight is on my right foot. I step out with my left foot slightly under 45 degrees about 1 shoulder width apart constantly keeping my head and eyes right above the shot line. My left foot is pointing in the same general direction of the shot line, slightly angled towards it. As I get down, I keep my eyes and head on the shot line and slowly begin shifting my weight to be evenly distributed on both of my legs. Both of my knees are slightly bent. My upper arm gets lined up perfectly with the shot line and the forearm will hang straight down perpendicular to the ground when the cue is near impact with the cue ball.
Consistency is Key
While there is a lot of variability in stance from person to person, what shouldn't change is your personal stance from shot to shot. You should strive to maintain the same exact stance on every shot. Some exceptions to this would be if you have to stretch over the table making it impossible to use your normal stance. If you remember back to the previous lesson about the fundamentals, I stated that pool is all about consistency. Consistently repeat the same exact stance every time you shoot and it will quickly become muscle memory and something you no longer need to consider from shot to shot; though it is good to occasionally revisit all of your fundamentals to ensure you have maintained good form and to make small improvements.
In order to develop the necessary muscle memory and consistency in your stance, your assignment for this lesson is to perform the Stance Practice Drill and score at least a 25/30 points three consecutive times. To perform this drill, you will need some kind of slight adhesive such as masking tape. Be sure to use something that can be easily removed from the floor. Mark the shot line on the ground and your preferred placement of your feet with the masking tape. You will then practice getting down into your stance on the same shot. The shot I used is the cue ball from the point aiming into the far corner pocket.
You will not be shooting the cue ball, but rather practicing placing your feet in a consistent spot and getting your body properly aligned over the shot line. As stated above, the toes of your shooting foot, center of vision, shooting arm, bridge, and grip hand should all be on the shot line. You should also be stable and balanced with your feet within an inch (2.5cm) of the placement that you have marked. Remember that your goal here is to consistently get your feet in the same spot to develop consistency and muscle memory in getting down on your shot. After each iteration of getting down on the shot, you should completely reset so that you have to get back behind the shot and set up again. It will do you no good to not practice placing your feet in the correct spot. Give yourself 1 point for each successful attempt where your feet are in the right spot and all of the above mentioned are aligned along the shot line.
Conclusion
Analyze the stance of the majority of top class pros these days, and you will find that they will, for the most part, follow these general guidelines. They will not cross the shot line with their shooting foot and they will have plenty of clearance for their stroke. Their legs will be spread at least one shoulder width apart, and their chins right above the shot line keeping their vision centered on the shot. Don't try to perfectly emulate a specific professional players stance, but rather identify the areas which most professionals conform to and do what is necessary for your own body to conform to those general guidelines to which I have listed above.
Completion Requirements
Read and comprehend this entire lesson
Find your stance that works for you starting from the above stance guidelines. Your stance should give you clearance, visual alignment, physical alignment, balance, and comfort.
Perform the Stance Practice Drill at least once every practice session until you score 3x consecutive scores of at least 25/30