Turn the barrel and come in from behind the ball! Yup!
Sadly, not everyone believes this.
Swings with a corner, the lower rear side pulling and sling shooting the swing.
No way can you train a hitter to see the ball, decide in the last 15 feet or so if it is go or not. Then think "I need to turn my lower half then my upper half" and expect them to be a high average hitter.
You need to teach them good mechanics to be reactive. Mechanics that show stretch between the lower and upper...but happening on auto. Lower going....or even worse "hips firing" are bs! Thats why you never hear much from mlb hitters talk of it. They talk all about hands....because their swing is reactive...only mental thought is about the hands.
Teach coil around the rear leg. Teach turn the barrel. And it is impossible not to be reactive. Like pulling back a bow, you pull back...you release when your target pin is near center target. You can spend the rest of your life working on perfecting the smoothest release and follow through, but the pull and release gets you 90% there. Just as a swing, learn to coil....learn to turn the barrel, and you are 90% there. The rest is details.