If the kid is analytically interested statcast has a great concept with swing zones.
https://www.google.com/search?...imgrc=bFKKOu-cTBNE5M
Tango has decided the zone in 3 zones
1. Heart of the plate (essentially the zone minus a 3 inch stripe around the zone)
2. Shadow zone (3 inches inside the zone plus a 3 inch stripe around the zone, pitches taken here are essentially called a strike 50% of the time)
3. Chase zone (more than 3 inches away from zone border)
Successful hitters generally swing very often in that heart and very rarely in chase. It is also good to take the shadow zone pitches but there are some exceptions
a) free swinging hitters like Jose Abreu or baez who can handle those pitches
b) guys like Mike trout who have a good eye but a differing hot zone. Trout takes a lot of pitches in the upper third of the heart and swings a lots of pitches slightly below the kneecaps which are often not called strikes because that is where he hits best
But goal must be to swing a lot in the heart of the plate. You can shift that heart a bit into a direction you like (for example up or in) but generally you still want to cover most of that heart because if you give up too much of the heart you give the pitcher too many free strikes.
Ideally the pitcher only has the shadow zone to work with because you crush the heart and take chase which means both lots of hits and walks.
You can also walk by taking heart pitches at lower level because you make the pitcher throw multiple times in the zone which many bad pitchers can't do but that approach won't scale at higher levels.
You see that even at higher levels. Hitters like Dan vogelbach or Tyler white are good examples for that. They both have an 80 grade eye and walked a ton in the minors and always had like a 900 ops in the minors because they would hit heart pitches well and take anything else which lead to high walk and OK K rates because pitchers could not get them to chase and not throw enough tough strikes.
But once they Made the majors they were forced to hit tough pitcher strikes which lead to their K rate skyrocketing as their contact skill and batspeed is not quite elite. They still walked but overall production plummeted.
That is why you still need scouting and not just watch stats. There are a lot of ways to produce a good OPS at lower levels that doesn't really scale.