Combine water, white vinegar and dish detergent in a bucket. Increase amounts as needed. Using a soft bristle scrub brush on an extension pole handle thingy, dip the brush in a bucket of the solution, and scrub it on the window. Before it has a chance to dry, spray/rinse it off with clean water.

Mix equal parts white vinegar and water in a bucket (you can also make it in a spray bottle). Optional: add a few drops of dish soap to help cut through grease and grime. Use a dry microfiber cloth to remove dust or dirt from the window surfaces.

Dawn. Nothing else compares. If the windows are REALLY dirty and or you'll be working in the sun, add a cap full of Glass Gleam 3 or 4 to your bucket with the Dawn. Blue Dawn dish soap.