Watch as many YouTube One Pocket Videos as possible. You can learn a lot; especially the pro matches. Also, play different people. People who are at your level and slightly better than you. Should help your game....
Books are great, but I totally agree with this. No better way to learn than watching video matches.
If you really want to get better, search up all the accu-stats videos with Bill Incardona commentating. I personally enjoy the ones with Danny D. along side but ... Grady is great as well.
I'd find little value in matches with kids commentating or matches with no commentating.
Depending on your general playing ability, controlling the CB is very important. In one pocket it depends many times on tangent line hits with slow spinning english to place the CB.
Another recurring situation is clearing multiple balls from your opponents area. Look for situations where you can hit the first OB to be cleared "straight on" so the CB can stop, sending the object ball into an angle to the second contact ball, thus clearing the two balls while dead stopping the CB. ( or hitting the CB slightly above center and firmly, clearing the two OBs and slow rolling the CB ahead slightly.
That comes up all the time .... Clearing balls while wacking the CB into the first ball on an angle will result in sending the CB running around.
Bottom line, you need to control the CB.
Also, learn about the carom line of the CB by aligning to the imaginary back side of the OB to be hit. A valuable tool that can be very accurate.
So ... spend some cash on videos .. and watch ... re-watch ... listen to commentary and observe table layouts.
You will get much more bang for your buck with videos IMO as well.