Things You'll Need
Instructions
Paint the exterior of your HO scale buildings using model paints and a paintbrush. Allow the exterior to dry overnight, but do not assemble the parts yet.
Cut squares from a clear styrene sheet with a pair of sharp scissors that are large enough to cover the windows in the building, leaving room for a slight overlap to the sides of the window for gluing.
Apply a thin bead of canopy cement, the modeling cement used for model airplane canopies to prevent fogging of the plastic, to the interior wall of the building surrounding the window frame. Press the styrene cutout over the window onto the glue. Smooth out any wrinkles using a toothpick, and then hold the styrene in place for 30 seconds. Wait about an hour for the glue to dry enough to continue.
Cut a piece of masking tape that's the desired shade color wide enough to cover the width of the window. Make a second cut to the tape to the length of your proposed window shade. Press the tape against the styrene, obscuring a portion of the plastic to give the appearance of a drawn window shade. Make sure the bottom of the tape is parallel with the bottom of the window frame. Cover all windows containing shades in this manner, adjusting the length of the shade to add variety to the windows.
Assemble the HO buildings with plastic cement to complete the building process.