I'll start with Practical Shooting: Beyond Fundamentals by Brian Enos. The book begins with a lot of mystical stuff about shooting: concentration vs. focus, meditation, awareness, etc. I'm not always sure about what to do with this. As I read over this section there's a lot that makes sense and fits with what I have experienced the past few years in practice and matches.
For example, Enos rightly notes that there is way too much going on when you are shooting at high speed to "concentrate" on any one thing or another. You really do have to let your subconscious mind take over. If you are concentrating on aiming, then you are way too focused on one thing. Everything needs to flow, to work together—grip, stance, splits, transitions, movement, footwork, target sequencing, reloads, gun handling, speed of engagement, execution of stage plan, etc. His point is that you cannot consciously think about how all of these factors will work together. Heck, you don't have time to think about any one of them in most cases. You just shoot.
This is why repetitive practice is so important. The shooter who doesn't make certain common skills "second nature" will have to think his way through too much in any given match. And that, of course, adds us to a huge amount of time and loss of accuracy.
I rehearse everything I will do on a particular stage before I get to the line—I concentrate on it. But when I raise my hands [get into the starting position], I also raise my awareness. I shift my control to automatic and shift my focus to the correct point to successfully shoot the stage. Then I quite my mind by focusing on the present tense as I immediately prepare to shoot. I no longer follow any plan. I stop thinking. I start shooting. And I act on what I actually see, not on what I planned on seeing (p. 22).I can relate to that. But I'm not sure I'm able to shut down conscious thinking and planning while shooting as thoroughly as Enos suggests. But it sounds like a worthy goal.