These drills are designed to push you. You have to think ahead and you have to deliver the goods. I usually integrate a couple of these into each of my practice sessions.
Challenge 1 – Take ball in hand on the first shot, then make the 1 ball in the upper left corner pocket, the two ball in the lower right corner pocket, etc.
Challenge 1
Challenge 2 – Take ball in hand on the first shot, then make the 1 ball in the upper left corner pocket, the two ball in the lower right corner pocket, etc.
Challenge 2
Challenge 3 – Take ball in hand on the first shot, then run the balls in any order you wish.
Challenge 3
Challenge 4 – And now for a real challenge! Take ball in hand on the first shot, then run the balls in numerical order. Randomly place ball numbers so you can try all possible permutations. If you can consistently run the table, you are well on your way to glory!
Challenge 4
Angle of Reflection 
I’m really liking (Challenge 4) — thanks for introducing me to it. I’m careful always to set it up with the 2 in the middle of the short rail and the 1 on a rail in the other half of the table, just to make sure I have something to think about from the first shot on.
A variant of challenge-4 I prefer to use has all six pockets blocked as well. Obviously they are easy to make, but it gives me a chance to play some different options Sink the blocking ball and try to get position on a second shot and sink it in the same pocket. Usually challenge 4 is played as rail shots – I rarely see anyone try it with bank shots. The same goes for challenge-3.