The one-word answer: YouTube! They got guys on there that give lessons!
And if you found that answer disappointing because you also can only run 3-4 balls and you think lessons wouldn't help you much because you've been playing for years and you already know everything about the fundamentals, then I've got news for you: there's a lot you don't know! The only difference between you and the guys who can run out when the balls are wide open, is they know/consider this stuff, and you don't! My brain is EXHAUSTED after an hour of practice right now, as I try to apply all that I learned on every shot.
Here's my story, which I'm posting here because I imagine there are a lot of pool players who can run 3-4 balls, and haven't seen any improvement in their game in years:
A couple of years ago I moved in with roommates who had a 7' table in the basement. I hadn't picked up a cue in 20 years, but I practically lived in the poolroom when I was a teen (I gave it up when I got old enough to gamble away my money on other things; at my best, I could occasionally run a rack, except for ALWAYS dogging the last shot, no matter how easy a shot it was, even in practice!). I had a lot of fun knocking balls around again on this seven footer.
My roommate saw my interest in the game, and grabbed his cue. It turned out we were pretty evenly matched. He could also run a few balls, and would also dog easy shots, even though we weren't even playing for money...but I would consistently beat him, because he never considered playing a safety, no matter how hopeless his position.
He was rather shocked by these results. He told me he was the captain of a pool team in a local bar league. At his urging, I joined his team. It's been a lot of fun, too. About 90% of the players in this league are just like us; and even though I'm the only guy using a house cue, I'm winning more than I'm losing because I'm pretty good at defense, in a world where no one even thinks about that.
Then I caught the flu a couple of weeks ago. Stuck on the couch for a week, I wandered over to YouTube. I was just looking for some pointers about 8-ball strategy, because I never played serious 8-ball back in my day, I thought it was a kid's game...and down the rabbit hole I fell! Here is just a sample of some of the things I learned in that one week:
--The Ghost Ball! I'd never heard of it. Aiming got a lot easier when I stopped worrying about controlling TWO balls. All I needed to control was the cue ball. If it hits the Ghost Ball spot perfectly, I've done my job.
--You usually don't need left/right English to get position. Often, you don't need top/bottom, either. Before YouTube, I never hit a shot WITHOUT English! I was Mr FPS (Fancy Play Syndrome). Funny, balls don't bobble in the jaws of the pocket any more.
--Get on "the right side of the line" when playing position. I'd never heard of this. I only had a vague idea where I wanted to leave the cue ball. This one thing led to a huge leap in my game.
--Do all your thinking before you bend over! What a game-changer THIS piece of advice was! I would miss so many shots because of all the questions/doubts that would flood into my head while I was over the ball. I *knew* that this was a problem. "My hands already know what to do, I just got to get my brain out of the way!" Now I commit to a plan before bending, and there's nothing left to think about. I just take a couple of practice strokes and think, "1, 2, hit." There's nothing left for the brain to do but watch the ball go in, while the cue ball reports directly to the spot that you imagined it would.
--The importance of keeping your right arm relaxed (if you're right-handed). Tension in those muscles, even the slightest tremor, can louse up a shot.
--Still having trouble with dogging that last ball? Here's a trick that has helped me tremendously: pretend it's NOT the last ball! When you're doing your "thinking before bending", imagine there's another ball you need to get position for after this one. Busying yourself with this position consideration helps to keep away those pesky thoughts of, "OMG,this is it, moment of truth, game ball, this means so much, what if I miss, what will my friends think of me?...", etc. Try it, it's awesome.
--Plan your entire runout before your first shot. I never used to plan for more than 2-4 balls. Guess how many I'd usually run?
There's so, so much more. Start with the novice stuff, don't skip anything. If I had skipped the stuff about the stance and forming the bridge, etc, I would have missed that stuff about keeping the right arm relaxed. I even picked up a tip about forming a more solid bridge when you're shooting over a ball and shooting from stuck on the rail. Again, I thought I knew everything (I told this to a friend, who replied, "Yeah, you DO think you know everything!").
So spend some time on YouTube. Look for vids by Jimmy Reid, Tor Lawry, and DrDave.
Freshly armed with this new knowledge, I went to my Thursday night pool league. In this league, our team of five guys plays round-robin against their five guys, one rack of 8-ball. I won four of my five racks. The one I lost, I never had a chance, the striped balls were hopelessly tied up and I got stuck with that suit. But in another rack, I beat a guy with a sky-high rating, who may be the best player in our league, I'm told. Before my YouTube week, I never would stood a chance against this guy...but confidence is a funny thing in this game. After I ran 6-and-out, I rejoined my teammates, who were rather surprised by the result. I told them that I was not surprised, that a little defense goes a long way in this league (my opponent, the "best player in this league", had not played a single defensive shot against me...though in his defense, he probably felt he didn't need to, as a guy with my rating shouldn't be running 6-and-out). I pointed out to my teammates that his last two balls were tied up in the middle of the short rail, and "...this game could have went six more innings, and those two balls would STILL be tied up there!" OK, I got a little carried away, but I was pretty pumped up about beating such a good player.
Different format in our Tuesday night league. Instead of round robin, the team captains match wits by arranging one-on-one matchups. Its so silly, watching these captains tanking over these decisions, when its a handicap league, which makes every match pretty much a fair fight. I was matched up against a guy with a near-identical rating as me, and sure enough, he was as advertised, about as good as I was before my very recent education. We played a race to four. I dogged a shot in the first rack, for the usual reasons--got nervous, heart pounding, what will my friends think of me if I lose tonight?--and he ran out.
But early in the second rack, he bobbled an easy shot, and all my nerves disappeared. My focus on each shot was incredible, it felt like I was the only person in the room. I destroyed this guy, won every rack the rest of the way, and none were close. My confidence grew; his crumbled. Soon we both knew he was drawing dead. I'd never experienced that before.
After the match, I told my team captain, "Next week, I want their best guy!" I'll let you know how that goes.
The following day, I went out and bought a new cue, first time I've owned a cue in over twenty years. Spent just over $150 on a Player. They let me hit a few balls with it at the store, but they wouldn't let me chalk it. I felt like this was the cue for me, even though it's hard to tell without chalk. I ran to a bar with it to hit some balls...and I never played better in my life!
Next day, back to the Thursday, round-robin league, and man, we were in tough. I have the highest rating on our team, but I'd be the lowest-rated guy on this other team. They were all good, and one guy is considered practically a pro (he had dismantled my roommate in that Tuesday league, two nights prior, beat him eight racks to two, with several long runouts).
My first game, I broke, and nothing fell, table was wide open. My opponent was clearly very good, and looked like he was going to run out...but he got a little out of shape after his fifth ball. He was able to make his sixth, but he left himself no shot on his last solid ball. He tried a low percentage shot and missed. He never considered playing safe on his last two shots.
I stepped up to a wide open table, thinking, this guy's good. I'd better not miss. I took a minute to map out my entire runout, which wasn't that tough. Not just the order I'd make the balls, but which pocket each would go in, and on "which side of the line" I should leave each shot. I visualized each shot before bending: aiming point, English, and speed. This is MUCH more thinking than I'm used to doing, and it's exhausting when you're not used to it. I got a little out of shape after my fifth shot, but luckily I was still OK if I shot my remaining two balls in a different order than planned. Made the simple stop shot on the sixth. Just make a straight in shot on the last one, draw back a foot or two for an easy shot on the 8...holy cow, I'm gonna run the table!
Those last seven words are exactly what you should NOT be thinking about when you're bent over. I made that seventh ball, but didnt get that 1'-2' of draw i needed. The cue ball stopped in the center of the table, leaving me a tough cut shot on the eight.
I hit it pretty good, but not quite enough speed, and it hung. I got lucky on the leave. He had nowhere to hide since the 8 was hanging, so he tried an impossible bank shot, but you could tell from his body language he thought he couldn't win, so he hit 1000 mph and scratched, giving me ball in hand. He conceded the gimme. First win in the books.
On the other table, my roommate was once again being dismantled by that same champion guy who crushed him Tuesday. Champ ran out, then came over to play me.
I aint scared.
He broke. Not a good break. Nothing fell. Cue ball ended up back in the kitchen. Only shot I REALLY dont want stripes here. Neither of us can run out the stripes, and he can probably run the solids. I try a long, hopeless combo instead, and it doesnt go. He sinks a solid, and i sit down, not expecting to get another shot. He makes it look easy, potting ball after ball. He left himself a longer shot on the 8 than either of us expected, and we were both surprised when he bobbled it.
With his balls cleared, my once-hopeless layout was now wide open. I ran out, but in stark contrast to my opponent, I did NOT make it look easy at all. I made the SHOTS look easy, but I was tanking really, really hard between shots. Again, all this thinking and planning is brand new to me. But I got the run out, aided by playing position on the imaginary 9th baIl so I wouldn't follow the hanging 8 into the pocket, lol.
I just beat a champ. Holy crap. Two weeks ago, i couldn't run five balls. A little more speed on that first 8 ball, and barring a hopeless combo, i just ran two racks in a row!
Third rack was a tangled mess. We each had four balls left when i played a pretty good safety. Now my balls were were almost wide open. I left the cue ball by a corner pocket. His only shot was a ball in the center of the table, but the two obvious pockets for it were blocked. He could only cut it to the other far corner, and if he did, he'd have no idea where the cue ball was going. He ended up making that shot, and two other shots that were just as difficult, while running out. Can't win 'em all, I guess.
Fourth match, made two balls, played safe, ran out when I got back to the table.
Fifth match, opponent broke, nothing fell, he sat down and watched me run out.
This is crazy! Thanks, YouTube!