As a HS coach I understood the strengths of my hitters. The one's in the line up and the one's not in the line up. Some coaches have a team approach at the plate. They attempt to run up pitch counts. They routinely take on 0-0 1-0 2-0 3-0 3-1 counts. Some coaches are big on situational hitting. Runner on 1st no outs will be a totally different approach than runner on 2nd no outs. In scenario 1 they are either in sac mode, drag mode, take and see until you are either in a hitter's count, or take and see if you can get a good pitch to run on, hit and run on, run and hit on.
My approach as a HS coach was to teach my kids how to actually hit. I always believed that the more you had in your head that had nothing to do with actually driving the baseball, the less success you were going to have driving the baseball. I figured if I could maximize their potential to actually hit some college coach could use that abiltiy the way he saw fit.
Over thinking the game, over coaching the game. Know your strength's when you get in the box. Know the pitcher's strength's when you get in the box. Are you watching the game? Are you communicating with the other hitters? Are you looking for what you want or what you are going to get? Is the pitcher working fastball's away and breaking stuff in the zone? Can he command his breaking stuff? All of this is information that is readily available by the second at bat of the game. And for some in the first at bat of the game.
I asked one college coach why he had his team take so many pitches. Why they routinely took pitches in hitters counts. He said the whole goal was to drive up pitch counts and get in the bull pen early. I said "You can get in the bull pen early scoring no runs by driving up a pitch count. And you can get in the bull pen early with some runs by making the pitcher pay for falling behind in counts."
HS hitters need to learn how to hit before they learn how to situational hit. Your asking a kid to hit behind a runner and he is just trying to square a ball up. Personally my opinion is you should step in the box with one thing on your mind. And that is getting a good pitch to P iss on. And when you get a hitters count be ready to unload. Not standing there hoping you walk. Not standing their surprised you got a grooved fb over the heart on a 2-0 pitch. Or standing there with a take sign on a 3-1 pitch over the heart. So now your in a 3-2 count and he puts you away on a slider.
So my answer to you is go up there each at bat with one goal. Mash. Once you can mash what you should be able to mash, it will all clear up for you.