The diagram below is among the easiest position drills I know of, yet I can think of few others as valuable.
With the cue ball located more or less in the center of the table, and an object ball near a side pocket, there is hardly a spot on the table that can't be reached for position, with minimum fear of scratching.
Set up the shot as shown. You will be trying three different position shots from the same starting point using high left english. First, try to leave the ball at position "A", then position "B", and finally position "C."
By hitting the cue ball high, the normal tangent line will be bent forward causing the cue ball to hit the first rail early. The left spin will carry the cue ball to the other points shown. If you you nearly scratch in the lower left pocket, you are not putting enough left spin on the cue ball.
After you have learned to reach the desired position points as set up, alter the shot a little and decide for yourself where you want to leave the cue ball using a similar hit. Remember that in a game no two shots are ever the same, so learn to make adjustments by practicing variations on the basic ideas.
I should warn you that position "C" will not be easy to reach, and getting there requires good spin technique, not just speed.
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