A few things. Best DVD's kinda got lost but I like Li'l Joe's at Pool IQ.net Note that is net, not com. The first two are more like drills, the third is an edited version of a three day live lesson, actually two DVD's in a set. Unless you find a good local instructor that can help you tune little things as you go, a coach as much as instructor, get set up to do video. Doesn't have to be fancy but being able to see what you do is often a big help. What a person thinks they do and what they do are often two different things regardless of level of play. Video Analysis is or was available. David Sapolis, Blackjack on here, is an excellent instructor that offered video analysis very reasonably last I knew. A good guy I recommend highly if he is still teaching. You can often see errors on your own too.
The critical part of the stroke is the final forward motion. There are a lot of ways to get to that though. Some like a slight pause, some a protracted one, some a smooth transition from back motion to forward with no perceptible pause, some use an elliptical stroke that has no pause. It doesn't matter at all which you use. The important thing is that there is no jerk when you start forward. Get very focused on a slow start forward for the first couple of inches until that is in your DNA!
Easier said than done but with practice it gets easier: Do your planning and alignment standing, once down on the shot try to avoid any thought at all. With practice you may be able to run entire racks as one continuous motion, no thoughts in words.
Hard to make someone understand the importance of a quiet mind and a quiet body. Those that understand are usually already there. Watch the players in any cue sport that seem to flow around the table and move very smoothly including their stroke. The effortless power comes from an accelerating stroke into the cue ball. Try to accelerate through the cue ball. That isn't technically possible but you can try to. When you hit the cue ball exactly where you plan to and have a smooth stroke good things happen. We usually aim with the middle of the tip but rarely hit the cue ball with the middle of the tip. Because of that you can struggle to get as far out on the cue ball as you need to or can try to hit further out than possible without a miscue. I think about halfway between center and edge is as far out as you can usually hit without a miscue. That is actual contact point, not what you are looking at from behind the cue. Too, front hand, back hand, and parallel english all allow a slightly different contact point. However, I have never seen it proven one was better than the other, the direction of force is a factor not usually discussed.
A simple stroke drill is to put a ball about four to six inches in front of the cue ball. When practicing your stroke, ignore the cue ball and try to hit the ball in front with your cue tip. Impossible of course but you will power through the cue ball nicely.
Pool has all the information to become a great player on the internet for free. Both on this site and on youtube. Unfortunately, lots of bad information too and there is little to tell you which is which. Find one pretty conventional path for starters and stay with it. Better to take as much advice as possible from one source or you may be trying to do things that don't work well together.
The mental game can be learned many places but there is a certain amount of experience required to perform under pressure. Some have a great deal of trouble performing under pressure, others improve their performance under pressure. Part of that is purely what you tell yourself. Having competed at many things I have listened to countless people complaining about things that don't suit them. Never stay around these people long, their pessimism is contagious! Far better to say to yourself that you love tough conditions because you handle them better than many competitors. I almost always move up in a field when conditions are bad because I don't beat myself up over bad conditions. Let others do that to themselves.
Try to find a good local mentor. Don't disagree with them even though they won't be 100% correct. Learning a very good way and then fine tuning can be more important than seeking perfection from a long ways out. Generally best to move up through the steps from crawling to flying than going from sitting in the nest to flying. Always thought it sucked to be a nestling bird, especially of the types that live in high places. How do you learn to fly? A kick in the ass and wish you luck! A lot of nestlings don't make it past that point. Fortunately there are easier learning routes for humans.
Enough of a book for one post. Oh, one more thing to toss out, don't forget to have fun! A weakness of mine, I get so wrapped up in competing I sometimes forget I am there because I want to be and to enjoy myself. I do have to say it is more fun to win than to lose though.
Hu