Honestly, I take and put a piece of paper on the wall, that represents a cue ball. It has to be the same height as it would be if you were on a pool table. This paper is over a table, and that table is the height of whatever table I normally would be playing on at my local pool hall.
On that piece of paper I draw a circle.
Then I line up my shot, using the kitchen table as a pool table, and the paper on the wall with a circle it (same size as a tip) as a cue ball. Then I proceed to practice stroking the cue into that circle on the paper. I do this 300 times. Rest, then do it 300 more, then rest a bit, then do it 300 more.
I've done this lots when I do not have time to go to the pool hall. It gets your arm lose and steady. Then when I go to play, I can tell a HUGE difference. I assume it's because it's like working out. I am exercising the same muscles, building memory into them. And when I get to the actual pool table, my arm is ready. It's been trained to be steady and accurate.
One other thing I do.
I throw out a whole rack of balls on a 9 foot diamond table. I take ball in hand, and run all the balls out. My goal is not to miss. I shoot whatever I want, like straight pool.
I do this 18 times, which is the number of diamonds on the table. Each time I move my quarter around the table. Once done I have just shot and made 15 x 18 balls, which equals 270 balls. This is one of the best practices I have ever done. The one thing it accomplishes is fluidity. I get very loose and fluid. Also it builds confidence, because you are NOT missing any balls. If you do by chance miss, you have to do that rack over again.
This drill takes about 45 minutes. At least with the speed I play. Which is fast.
When I do this, and then play in a tournament later that day, I have found it to TREENDOUSLY make a difference. Many times, more than not, I either win the tournament or at least get 3rd place.
Now, mind you, I am above average of a player, many, I am above a B player, more like on the upper end of a LOW "A" player. I play maybe once a week, more like 2 a month, and can still maintain that level. If I could play more, I am sure with the above practice and adding regular play time, I would advance surely.
I play people who are rated at least 2 ratings higher than me, and they play regulary, I I can still beat them at least 50% of the time without even playing even close to the amount they play.
My point to that, is that what I am saying works, at least for me....