One recipe calls for one part white vinegar with two parts water, and you can add a few drops of dish soap or essential oil for a pleasant smell. Spritz it on the glass, and wipe down the another cloth in a Z-shape.
Clean the outside of the window
This is likely where the real mess is. To get the exterior of the windows, you may want something stronger than spray cleaner.
You start by taking off the screen and wash them separately by hosing them down with water. Then clean the glass with soap and water. Make sure you dry them with a squeegee, or else water marks will be left behind.
