Enforce the rules you have in front of you.
If you do not watch the number of warmup pitches that are taken. Limit the times the batter leaves the batters box(NF). Limit the time conferences are taken, you can limit the time the game takes and most of all, call STRIKES. Stop making pitchers of HS and below become Pedro Martinez with their pitches.
If many umpires in my opinion do not take care of business when they should, games take longer. I rarely have a game that takes 2 hours. And when I do, it is because so many errors are made or the pitcher could not hit the broad side of a barn. All those are out of my hands in the first place. This is why I love college games so much. The style is most different than all other levels. They do not mess around, they challenge hitters and make them hit it.
Peace