The book is outdated, gets things wrong in places, and sometimes there are better alternatives. I respect Ray Martin, but he is no Dr. Dave/Bob Jewett. Dr. Dave did a video covering 10 of the shots in that book. I think the op would be better off going through all of Dr. Dave's videos. He could pick one, watch it, then spend 20 minutes practicing what was in the video, then go on to the next video. When the op is done with Dr. Dave's videos, he could even circle back around and do them all again to ingrain what he learned. I think that would be way more educational, and afterwards the op would understand how things actually work on a pool table, and he would be able to apply that knowledge to any shot.
Of course, Dr. Dave trains your pool knowledge, but you still need to train your stroke by practicing rock solid fundamentals. If the op is interested in learning and practicing the fundamentals of the stroke: "Play Great Pool" by Mark Wilson.
This is exactly what Bert Kinister had me doing, table length stop shots from corner to opposite corner. Not just any stop shot, but perfectly replace the object ball with the cue Ball in a paper donut. I used to shoot this shot 100 times a day when I had my own table, and maybe hit it perfect 3 to 5 times out of 100. It was so difficult, but eventually I became ultra aware of the cue and the feel of the tip contacting the cue Ball. That feel took my game to another level for sure, plus my stroke became very accurate. Speed control and accuracy improved drastically. You can not play high level if "your gun doesn't shoot straight."I would spend those 30 minutes a few times a week shooting different length stop shots to make sure the stroke and aim are solid at your skill level. Straight in shots, make sure the cueball is not drifting off the line or is spinning too much after contact, practice at different distances to tune in how well you can do a stop shot at length, which will also help with your draw and follow shots as well since how you hit those also depend on the distance. To get past just an average league player you need to master playing position from and to all parts of the table, which requires speed control at different shot lengths. Almost any lower level player just has no stroke to do what they need to and end up at horrible angles and table length shots to shoot all the time. If you learn to shoot a stop shot at say 3/4 table length that is the beginning of getting the stoke and control needed to play most shots. The rest of the time what you are doing should be OK but keep in mind you would want to practice any shot you messed up several times to learn how to shoot it properly.
A wise pool bum once told me when I was whining about familial duty:All do respect, but that spare time. Spend it with your kid. I was getting better when we had our first kid. I would set her on our centennial table with a baby Minnie Mouse blanket and let he have a toy. I would shoot balls around her on the table. It taught me to shoot easy, along with shooting different English on soft touch shots. Pool is fun. But our kids are a blast, enjoy them when you can.