Start top left.
Scrub the top of each frame then immediately the sides and top of cill, then go back over the glass immediately scrubbing well.
Do the same at the next set of windows etc.
Now go back to the start and just clean the glass (you can touch the top of the frame a bit) thoroughly again and rinse.
Now do the same at the bottoms.
Blade off any entranceway doors (don't worry about side panels).
Are you doing insides too? If not and you can gain access then thoroughly clean the entranceway glass on the inside if it's only a couple of doors.
Get someone to sign that you have completed the work if you are invoicing and have any doubts about payment.