I'm a housekeeper, part-time. One of the houses I do has got to have close to 30 or 40 windows (and we're talking 5 foot tall windows. Beautiful view, on top of a mountain, so I don't really mind cleaning them.) Let's just say, I'm well-versed in windows.
The trick to clean windows isn't the solution you use to clean it. It's to use a SQUEEGEE.
For the outsides (of the ones I can reach), I use a mix of Dawn diswashing detergent (just a squirt) and water in a spray bottle. Spray on, scrub with a sponge, squeegee off. Wipe the squeegee in between passes. If you have any stray lines, buff 'em off with a DRY microfiber cloth. (I buy microfiber by the yard from a fabric store on Hyena Cart. It's much more plush than the junk you get in the stores. The microfiber cloths from the auto department at Costco hold up well, but not as well as the stuff by the yard.)
For insides, I use the soap mixture if they are dirty. If it's just a routine cleaning (as in, I've been cleaning the house weekly, so the windows are clean anyway), I use a mix of rubbing alcohol and water (4 parts alcohol to 1 part water. Sometimes even less diluted than that...I just eyeball it.) and the squeegee.