Duke William of Normandy won the battle because was well prepared and had a good army. They prepared carefully for the battle. The Normans had knights on horseback who were skilful fighters.
A utility knife, metal ruler, and a hammer can be faster than trying to carefully saw an opening. Score the drywall a couple times till you are most of the way through, then just knock a hole with the hammer and break the drywall back at the score lines.
Insert screws with a screw gun or a 3/8-inch drill. Space drywall screws approximately 12 inches apart when installing drywall on standard wood studs and metal studs on walls and ceilings.