If you have to use a ladder, get stand off stabilizers like this one. I use this one because it is removable so when I have my ladder stored on the top of my truck, the legs do not stick out into other lanes of traffic.
I also have a leg leveler for when I have to set the ladder up on drastically uneven ground.
Face to glass is the best way, especially if you are doing a first time cleaning, or are just starting out. It allows you to see the results and allow you to correct mistakes. It takes a while to get a pole technique good enough to be confident in your results with out inspecting it up close. It is also better to do it during maintenance cleanings rather than initial since you are cleaning lighter accumulations of dust and dirt rather than caked on grime, etc.