So, we've narrowed it down to about 850 basic rules to use, plus the understanding that all of them are situational and interactive. Ultimately, the best way to "Gitgud" is to play a lot of games against different opponents with different playing styles and units. Eventually it all starts to make sense. That's why fighter pilots run dozens of combat simulations and training missions before facing any real opponent, and why the Veteran pilots tend to stay alive while the rookies have a high rate of turnover. Situational awareness and familiarity are a huge part of it, and you can't grasp the "big picture" until you intuitively understand the details that form it. The best way to do so is by experience.
As a young tech, I was able to learn how to use an oscilloscope, and hunt around blindly for something that looked amiss. Eventually, I was able to trace problems back to find the cause. Now, with a few decades of experience, I can look at the symptoms and already have a pretty good idea of where to start looking, if I don't recall seeing the same thing before and know exactly what's causing it. The same applies to any complex task, where you begin with the individual basic concepts, learn enough about them to understand WHY things are happening, and only then will you be able to view the "big picture" and apply your knowledge to resolve it.
The other point I should stress is that people learn best from their own mistakes, so if you don't play or if you repeat the same moves over and over in the same situations because they work in that case, you don't make many mistakes, and you don't learn. Push the envelope, do things differently, learn the lessons, and when you've gotten a grasp on it, push further. In theory, making as many mistakes as possible should be a shortcut to perfection, and therefore a good thing, but for some odd reason my employer doesn't see it that way.