Here's what helped me drastically improve my pitching:
The CPU seems to want to hover their batting icon over their batting hotspots.
So pay attention early in the at-bat to where the batter wants the pitch, and DO NOT PITCH THERE.
This has improved my pitching so much. I am giving up like 1 to 3 runs a game now with my starters. Too bad my bullpen got bought at a flea market sale or something. These dudes cannot close a game even if I give them a half-dozen runs to work with.