I use bug and tar remover on the outside glass with a clean microfiber cloth to buff.

I have also had good luck with 90+% isopropyl alcohol from walmart in certain cases. It really depends on what is causing the streaks.

I also clean all my windows before I was the car. This is because the window cleaning solutions seem to drip down onto the doors and whatever crud I've washed off the windows ends up on my paint.

By the way, ammonia-based cleaners never work for me.