take a packed lunch and flask every day to work.it saves money and cuts down time faffing about going to sandwich shop/chippy.
dont try and cram in too much work in a day as you ll suffer the next day(6 or 7 hours "on the glass"a day is enough for me)
use shoe covers for any inside window cleaning.looks more professional than taking your boots off!
always carry a good stock of clean dry cloths/cleaning chemicals/brushes etc
have a toolbox with lots of spares(connectors/tape etc)
have a spare pump, hose reel, hose and emergency back up pole in your shed/garage/storage space