Try tunneling your pitches and don’t hang breaking pitches high. Throw curveballs and most breaking pitches out of the zone. Start them in the zone and then they break out of the zone. Use hitters swings as weaknesses. If hitters have long swings throw hard fastballs inside. There a lot of different things you do to keep a hitter uncomfortable in the box. Watch professional pitches and try to learn from the best,
Also pinpoint is a must. Without pinpoint a bunch of pitches will end up in a terrible spot in the zone.