Mix 1 part white vinegar and 10 parts water in a spray bottle, or use an alcohol and ammonia-free glass cleaner.
Apply the glass cleaner to a microfiber cloth or paper towels. Wipe the interior of the window thoroughly in one direction, using straight strokes to remove any dirt or dust. Use clean cloths or paper towels, and apply more glass cleaner as needed.
Spray the exterior windows with a garden hose to rinse away any dirt or debris. You can also clean the windows on the outside using the indoor method. Use a ladder if necessary to reach the windows.