First you need the right equipment. Do not use windex! The amonia leaves terrible streaks. Its is great for getting oil off, but nothing else. I don't recomend it, but if you must use hand cleaner, get a kind that comes inan arisol can, non amonia foaming glass cleaner. It will work the best, and use clean, dry, folded surgical rags, not paper towels. If you are alergic to other cleaning chemicals, you may be alergic to this. So use caution. Otherwise you can find most of the equipment at your local Lowes or Home Depot and the rest at janitorial supply places, though if you go to the later, you will pay an inflated price for the equipment. All pictured below.

     1; 8 inch squeegee for smaller or french windows.

     1; 12- 20 inch squeegee the kind with interchangable blades

     1; mop head and cover at least 10 inches, no larger than 18

     a few rags. surgical rags are the best, because if they are clean they don't leave residue

     a screw driver, phillips, standard, and a nut driver for hex head screws, depending on your screens

     Dish soap

     A bucket

     A heavy duty brush for the screens, or you can scrub them with the mop and hose them off.

     An old towel, to catch the water when you wash the inside windows.

     And if you have paint or hard water on your window, a rasorblade scraper with a safety cover (very important) and a none abrasive scrubung pad or steel wool.

On a side note....Don't let anyone tell you you need anything special to go in your washing water, dish soap is the absolute best thing to use. And if its to hard with that to get hard water off, you can use bathroom cleaner directly on the window, make sure its the kind that eats away saop scum, lime and hard water. If you do use that stuff, Wear a breathing mask, and change your bucket water often, especially before you start on the inside of the windows. And rinse your mop out as well. And be careful not to get it directly on the paint of you hows below or beside the window, it may act as a paint remover.

     First you must fill your bucket with water, hose water is fine. Then put at least a half cup of dish washing soap,(not the kind you put in the dishwasher, but the kind you use by hand) in with the water and swish it around with your mop. Next take the screens off and brush them thoroughly, or wash them if you wish, though that is more time consuming. You may have to use a standard screw driver to pry some of them out, but me careful, once a screen is damaged, you can't fix it. then brush out the window track and sill as much as possible. This keeps mud from building up in he track, or running down the wall of your house. If you are inside, place your towel along the bottom of the window to catch the water driping down from the squeegee, its the easiest way to deal with the mess. Then dip your mop in the bucket and gently wring it by running you thumb and pointer finger down it making the ok sign so it is not driping, bu still considerably wet. Then mop the widow so that it is ompletely wet. If ther is a dry spot on it it may streak. If there is hard water or paint on you window, try using the scrubing pad on it first and test it with your squeegee in a small area to see if its working and getting it all off. If not then you have to use your razor blade. MAKE SURE THE WINDOW IS WET WHEN SCRUBING AND RAZOR BLADING! Because if it is not, it will permanently scratch the glass. once all of the paint or hard water is off, it may take some time, re-wet the window, and squeegee it off. There are three different tecniques to do this the first is pulling the squegee down from the top to the bottom starting at one edge and working your way to the other. if you use this method make the squeegee point slightly downward in the direction of the part that you have already squeegeed, this avoids streaks. The second method is to move from one side to the other holding the squeegee perpendicular to the ground. And then work your way down to the bottom repeating this. The last method is the best, but hardest to do. I call it "the wave" This is what the professionals like me use. start at the edge of the windowwith the squeegee at a 45degree angle facing up. move it to the top and run the edge of the squeegee alone the edge of the window changing you posistion as you go, hiting each corner.Its more accuratly described in the picture below;