How do you lay off low pitches? I seem to swing at every low change up and curve low out of the zone.
Just don't swing for an entire game.
You're taking Ls anyway (I assume) by not laying off. Spend a whole game just watching every pitch you possibly can. When you're at 2 strikes, "get late" and try to foul off a bunch.
And then just track every breaking pitch that drops below the zone. What you'll start to do is create a picture in your mind of how much "smaller" the strike zone actually is than the box.
When you're at that point, you'll start to realize that almost everything people throw is worth laying off.