Working the Count
Taking pitches to get a better one and tire the pitcher.
How it actually works. Ahead in the count, 1-0, 2-0, 2-1, 3-1, you can look for one pitch in one spot and let everything else go, because a strike there costs you very little. Behind in the count, you have to cover more of the plate and more pitch types. Good hitters are not taking pitches for the sake of it. They are sitting on the pitch they know they will see at some point in the at bat and adjusting what they will swing at as the count moves.
Why it is done, and when it is wrong. The best version of this is personal. Figure out your swing and which pitch you do real damage on, then hunt that pitch in the counts pitchers actually throw it. If you crush fastballs up, the first pitch and 2-0 are your counts, because that is when a pitcher wants a strike and reaches for his heater. It also works on the other team. Long at bats run pitch counts up and get starters out of the game early, and a team that does it as a group wears a staff down over a weekend.
What people get wrong about it. Taking is not the goal. Taking a fastball down the middle on the first pitch so you can see one is a mistake dressed up as discipline, and it is often the best pitch you will get all at bat. Work the count by being selective, not by being passive.
At Little League and travel ball. At the younger levels the simplest version wins. Walks are common, so a hitter who will not chase ball four gets on base a lot, but a kid who takes every first pitch is falling behind against the pitchers who can throw strikes. Be ready to hit the first strike you like.
Batter's Eye: look up anything in baseball