A brick building project I made from drywall for my 1/25 scale model neighborhood, an up and coming diorama scene of total destruction.
This project was constructed with 1/2 in. thick drywall. Wet the good side with a sponge and hot water. Keep the surface wet for about five minutes and start attempting to peel off the paper coating. It should peel right off leave a brown layer of paper backing. Start again, wetting that paper and remove it by peeling or rolling off with your bare fingers (friction style).
Now they we have all the paper off, we can start cutting the mortar lines with a knife and ruler or straightedge. Windows and doorways can easily be cut out now as well. I used hot glue to bind all the walls and cut some small strips of lumber for roof trusses. The window frames are the large popsicle sticks hacked up.