How hard to press onto the glass ?

Hello everyone. I have just completed a business and I have noticed a few faint scratches on it, nothing major thankfully. Would it be because I press on to the glass to hard, it's this even possible ? How hard or not does everyone else press on to the glass to clean it. Thanks

The harder you press the more likely you'll be to scratching the glass but that will only happen if your brush is dirty.

Unless you're trying to remove a bad mark the pole shouldn't  be bending under pressure from you. You're also expending more energy then you need to.

The vast majority of dirt on glass is very loose, atmospheric soot and stuff that the wind has blown on to it. With a couple of light passes and a rinse everything is usually gone. Pollen/spider poo and bird poo being the exceptions.
 The tougher stuff to clean is the corners usually, which is where the cobwebs sit, also green algae and lichen on the sills and moss caught in the seals