[CBeisbol]

I let my assistant GM handle the vast majority of my minor league players

I control the important ones

First, I lock them to whichever level I think is appropriate for them. This is based on ratings, stats and age. The "appropriate level" is the highest level at which they won't be overmatched. The "view ratings relative to" button is helpful here

Second, I force start to to ensure they are playing and playing where I want them to play

That's about it.