One tip in another forum I picked up (and might be in the above links), clean outside glass going in one direction (left to right), and do inside glass (up and down). If there are streaks present, you will know which side of the glass to focus on. That's a start, the rest is dependent on towels and cleaner.
For crud covered windshields, I have been using S p i c and span glass cleaner. I have found this to so far be the best most powerful cleaner for bug splatters. For general light duty cleaning, Stoner's all the way or Glass Plus. -Ed