Don't be afraid to call a professional. It can be easy to damage windows if professional techniques and equipment are not used. In the long run, it can be cheaper to call a professional.
Stay safe. Do not put yourself in a position where you will endanger your safety. Always conduct your work in a controlled and safe environment. If you are using a ladder, ensure that it is safe and that you have an additional person at the base of the ladder for safety.
Use the right equipment. High-quality equipment can make you work more efficiently and can make tricky tasks easier. A high-quality cleaning solution will allow your blade to glide on the face of the window, therefore decreasing streaks and marks.
Avoid cleaning windows in direct sunlight or in windy conditions. Harsh weather conditions will cause your cleaning solution to dry quickly on the windows. If you then use a squeegee to dry a semi-dry window then streaks will be left.
Start at the top, work down. Always start cleaning windows from the top of the pane so that no water drops down the window after you have dried it.
Use an environmentally friendly detergent. Reduce your carbon footprint by using an environmentally friendly detergent. Most detergents are harsh on your skin and will cause your hands to dry out, an environmentally friendly detergent will not dry your hands out as severely.
Wipe your edges, if they are not dry. Dirt will build up on the edges of the window if you do not dry them. The next time it rains, that dirt will then transfer to your windows.
Get help to remove any objects in the way. Your back is too precious. Do not lean over any objects as you are cleaning windows, as you can damage both your back and the object. If the obstacle is too heavy to move comfortably yourself, then make sure your recruit another person to assist you.
Don't use too much detergent. Excessive detergent usage is not cost-effective. Only a small amount of detergent needs to be used in your cleaning solution.
Stare at your windows. After you have cleaned the windows, examine them from different angles, from both inside and out. If you only look from one angle, there may be marks and streaks that are not visible until you look from another angle.