IMO, there are two distinct parts to hitting, and BOTH parts are required for successful hitting. First is the swing mechanics - which has been discussed a lot on this forum. The other half is timing, pitch recognition, and decision making - all of which aren't talked about a lot.
Timing and recognition are somewhat related to mechanics, in that timing can be practiced with different speed pitches, and recognition is visually picking up and tracking the ball. Decision making is simply knowing when to swing and when to hold.
I don't see "good decision making" being taught very often. The count, number of outs, position of baserunners, accuracy of pitcher, and lots more all figure into the batters decision making. Knowing where to place the bunt for effective baserunning is very important. Knowing when (and how) to hit opposite field has become a lost art. But the catch is, it has to be sort of second nature for the batter. They can't go to the plate with a cluttered mind. It has to be automatic.
I think every batter should walk to the plate with a "plan", which starts with knowing how to make good decisions.
I admit I am not very experienced at knowing "how to work the count". But I will toss out my opinon - anyone please correct me and give me your thoughts:
0-0, 1-0, 2-0, 3-0, 3-1 = Patience; pick your pitch; pitch has to "come to you"; narrow strike zone
0-1, 1-1, 2-1 = Even count; slightly less selective but still patient, slightly wider strike zone
0-2, 1-2, 2-2, 3-2 = MUST identify close pitches - must make contact; widest strike zone