This progressive exercise to improve your shooting skills is in the book Drills & Exercises for Pool & Pocket Billiards.
This is a simple center ball hit. This drill dis designed to teach adjustments for the first rail contact point, based on the cue ball position on the table.
Take some time to dial in the correct contact point. Then experiment with different slow and medium speeds. It’s a good idea to shift the cue ball up and down one or two ball widths. This helps you dial in the small adjustments. It is VITAL to know how to consistently succeed with one rail kicks. (Not to mention a discouragement for your opponent to attempt hidden ball safeties.)
1.Use donuts to setup the CB positions on the table.
2. Practice the kick with a medium speed until you know the exact point where to aim the cue ball.
3. Shift the cue ball to each side a ball width and repeat.
4. Also shift the cue ball forward/backward and adjust the rail contact point slightly.