Measure and mark the cut line on the sheetrock
Place the sheetrock on a flat, stable surface
Use a straightedge to guide the cut
Score the front paper layer with a utility knife
Snap the sheetrock along the scored line
Cut the back paper layer with the utility knife
Use a drywall saw for outlets, curves, or irregular cuts
Trim rough edges with a utility knife or rasp
Wear safety glasses and a dust mask
Check the fit before installing