The purpose of the grip hand/arm is to simply hold the cue up and get forward momentum into the cue; NOT guide the cue left or right. It was the job of your stance to get your arm and the cue on the shot line. It is now the job of your grip hand and arm to get forward momentum into the cue. An object traveling in a straight line will continue along that straight line unless acted upon by an outside force. In order to take advantage of this, it is recommended that you use a light grip and keep your wrist relaxed. There should be no purposeful movements below the forearm. The wrist may need to bend slightly at the back and follow through of your stroke, but should be perfectly straight with the arm at contact with the cue ball.
How to Grip the Cue
Your fingers should wrap around the cue holding it on the bottom and outside. The thumb should point straight down and press against your pointer and middle finger to prevent the cue from moving left or right. Essentially, your fingers from the fingernail to the 2nd knuckle are holding the cue up, the part of the fingers from the 2nd to 3rd joint locks the cue in from the right, and the thumb locks the cue in on the left side (if you are shooting right handed). Gravity will do the rest to hold the cue in the grip. The grip should be firm enough to keep control of the cue, but loose enough to let it freely lay on the different fingers as it moves back and forth. Most of the weight of the cue will rest on the middle finger when striking the cue ball. Near the back of the stroke, weight will be held mostly on the pointer and middle finger. Near the end of your follow through, weight will be more distributed along the middle, ring, and pinky fingers. Lastly, ensure that your wrist is relaxed and hanging straight down.
♫ Hold on loosely, but don't let go. If you cling too tightly, you're gonna lose control ♫
Common Mistakes
Some common mistakes are to grip the cue too hard or too loose. A tight grip will magnify any slight imperfections in your stroke and requires too much engagement of your forearm muscles to allow for a smooth and accurate stroke. A grip too loose doesn't secure the cue efficiently allowing it to drift off course. A lot of players also tend to grip the cue too far back or too far forward. This takes them too far from that desired 90 degree angle limiting either their backswing or follow through. Lastly, some players will bend their wrist in or out to get the cue over the shot line. This is more of an issue with their stance as with a proper stance this wouldn't be necessary, but it is something to keep in mind if you find yourself having to bend your wrist.
Where to Place Your Grip Hand
Where you place your grip hand on the cue will vary from shot to shot based on your bridge length for the shot at hand. The longer your bridge length, the farther back your grip hand will be. What really matters is that when the cue is at address with the cue ball, your arm should be perpendicular(90 degrees) to the cue. Some top players, especially from Taiwan, play slightly choked up on the cue, but are still not too far from 90 degrees.
Stroke
The only part of your entire body that should be moving when you are shooting is your forearm like a pendulum. Be sure to avoid dropping your elbow during your shot as it has no real benefit and only serves as an additional movement that you would have to spend time mastering. The wrist needs to stay relaxed and at no point should your grip arm be guiding the cue left or right. It is only moving the cue forward and backwards directly on the shot line. Additionally, the acceleration of the cue should be smooth. Jerking your cue forward and backwards engages more muscles which will make it much more difficult to deliver your cue accurately. At all times through the shot, your grip, arm, shoulder, and the cue should be directly on the shot line. I will cover more on how to stroke the cue in the lesson on Shot Routine.
The Stroke the Line Drill is a great helper in identifying any unwanted left or right movement in your stroke. This single movement is the one you need to master, so you ought to make a concerted effort to identify any major flaws you have as quickly as possible. This drill will help you identify any left or right sway in your stroke. This drill is all about visual feedback, so there is no scoring system or required passing scores. Perform this drill by lining up your cue along the line between the felt of the rail and the wood of the table. Set up to the shot with a proper stance and stroke your cue forwards and backwards with warm up strokes as if it were a normal shot, and then take your last stroke and follow through like normal. Be sure to watch your cue the entire time to identify any unwanted left or right movement. Be sure to get to a place where there is no visible left or right sway in your stroke before moving on to the Shooting module.
Conclusion
The role of your grip hand and arm is to get the cue up to speed and deliver the cue accurately along the shot line that your stance has you gotten you set up to shoot along. Avoid any movement other than that of the forearm that should swing like a pendulum. Your wrist should be straight, and your grip should be loose enough to allow the cue to move straight, but not so loose that it isn't secure.
Lesson Completion Requirements
Read and comprehend this entire lesson
Practice the Stroke the Line Drill until your stroke has no visible horizontal movement in it