I've been using a variety of methods to clean my car windows but most specifically the windscreen.
I'll outline various methods and hopefully some of you can add to what I do (I don't mind criticism as long as it's constructive).
For a quick clean I wipe down the windscreen to remove crud (water and a microfibre towel). Then invisible glass cleaner applies with microfibre to finishes it off.
For a better clean I've been using:
1. 50/50 mix of water and vinegar.
2. Isopropyl Alcohol (rubbing alcohol)
3. Washed it with rubbing alcohol, then vinegar, then again with glass cleaner.
I read somewhere that a common modern misconception for leaving your car windows without streaks is to use newspaper. That may have worked well in the past due to the solvents and abrasive grit used in the ink, but new water-based inks just leave your hands blackened and smudgy.
Microfibre cloths: I find the "cheap" ones leave "sparkles" on the windows. By sparkles I mean, when looking out (from inside) with a light source shining from outside (Sun, torch etc) there are flecks of fibre glass looking sparkles. This doesn't happen with "good quality microfibre cloth. Note: These sparkles would also be on the paint work, except, of course you can't see them.
The cheap microfibre cloths gives no indication what they are made from. The better quality ones are usually made from 80 % polyester 20% polyamide (or 87/13 or 70/30.....I think 80/20 is best).
If your car has aftermarket tinted windows, do not use an alcohol-based glass cleaner. Instead, just clean tinted windows with soapy water (one drop of detergent in a spray bottle of water is sufficient).
You may have a clay bar and think it’s only for cleaning the paintwork, but a clay bar does a great job on glass. Use warm water in a spray bottle (warm water loosens grime better than cold water) and spray plenty of it onto the glass. Work the clay bar in all different angles. If you feel resistance, concentrate on that area to remove the embedded contaminants. Keep spraying plenty of water on the glass.
There is more I could add to the above but, will wait to see if other members are interested before adding more.