Highly recommend Joe Tuckers "Guaranteed Improvement" book. Its $11 at his site. It focuses on cue ball control. You score yourself. Great book to become better at pool, AND to keep focused. It keeps you focused by scoring your results, and recording them.
I've played 1000 per/game one hole a few times, and let me tell you, coming close to breaking your own score in this book is just as much pressure and focus.
I have that book and IMO it's in the very top of shot drill books or dvd's. Some look easy when you read them, but scoring high on a lot of them is hard. I use to do half of them every morning and the other half the next day. I'm going to go back to that. Johnnyt