I didn't have any coaching that made a fundamental difference until high school. In high school the pitching coach was a former player with two years minor league experience. Before high school skills came from playing, playing and playing before the evening organized baseball game or practice.
My LL coach was great because he was fun and we won the league. He was good at selecting players. Seven players from my 12yo year went on to high school baseball. All seven were college athletes (five baseball). When I was fourteen I asked him how he picked his team. He said after the obvious baseball choices he took kids who were athletic and not tense.
My Babe Ruth coach was a drunk who always had beer on his breath. He was only coaching so his kids could start. They stunk. My fifteen year old season I got the rest of the team behind me to tell the coach if his kids start at short and center, we quit.
My daughter managed to endure me from 7/8 machine pitch all the way through softball showcase ball. I was an assistant from 12u through showcase. She never did any extra work away from practice until summer after 8th grade. I didn't even consider the possibility she could play college ball until freshman year of high school. Once in high school softball became a year round effort despite playing two other sports.
I was the head coach for my son from 7/8 machine pitch through 16u (post freshman year). The last season he started tuning me out. As I stated at the time, "I need someone else to kick his tail to the next level." One of the local showcase coaches heard me say it and made an offer. He played showcase ball the next season (not for that coach). They had contacts I couldn't dream of. I also paid a couple thousand for pitching and hitting lessons after his soph year so other instructors could fine tune him on things he was tuning me out. My son also made baseball a year round effort in high school even though he was also playing soccer in the fall.
My daughter was in a travel softball organization with great head coaches from 12u and up. When my son played 13u to 16u travel ball I put together a coaching team of former college (two former pro) players. Both kids entered high school very well coached and fundamentally sound.
The hard part as a dad is post high school and having no influence. The kids are gone from home. They spend their time around college coaches. The only thing I've said post high school (in private) is asking if they were aware they're holding the bat higher or lower than usual. More often than not it was an intentional adjustment. My daughter's batting stance always drove me nuts anyway (think Marlon Anderson starting with his bat on his shoulder).