I have been washing windows this week. A pretty big job because we have lots of windows in a two-story house. I tried a couple of different home-made formulas for the washing solution to use on the outside windows and decided this one is the best:
1/2 bottle Jet-Dry or other rinse agent
1/4 cup ammonia
4 Tbs. alcohol
1/4 to 1/2 cup dishwasher powder
2 gallons of hot water
On the easily reachable first floor windows I used a car washing mop. I saw this recommended on a blog and found it very helpful and effective. On the higher windows I have an extension pole and a microfiber scrubber (used with a squeegee to wash the inside windows) which I attached to the pole. The method is to first spray the windows with water, scrub them with the solution, and then rinse by spraying again. After trial & error, I found that you can't rinse too much. A couple of the first windows I did had streaks from the solution running down, so I redid them.
This is an excellent method for a house with only first floor windows; for the second story I seemed to be taking a shower with every rinse, but the results were worth getting wet. Otherwise, I have the crank out windows which can be washed from the inside but it is a cumbersome job.
Inside I use vinegar and water with the above mentioned scrubber and a squeegee.
Such a great feeling to have sparkling windows!