Check your alignment and your ability to see the placement of the tip on the CB, and how straight you stroke:
Place the CB on the foot spot where racks are spotted. Freeze an OB on the head short rail exactly in the center. Some tables might have a brand logo there; some a diamond. If a logo, do your best to find exact center, mark it with a piece of chalk.
Get down on the shot.
To check alignment, look down at the cue. If you are aligned properly, the cue should be DIRECTLY over the center diamond of the foot rail.
To check stroke, shoot at the OB for a full hit. If you hit it square, the CB should rebound exactly down the center of the table. If it rebounds to either side, that tells you on which side you diverged from dead nuts on.
An advanced version of this is to place the OB on the head spot and shoot a stop shot. If hit square, the OB should rebound exactly off the head rail and come back up table and hit the CB square. This will test not only straight cueing but your ability to hit the stop shot with zero side side spin of the CB. If you hit it with even a little side spin on the CB, even if hit square, some side spin will be transferred to the OB and the OB will not rebound square.
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