I've a few:
If you don't want to take your bucket of water with you (for example over a garage to do a large rear with a conservatory - or to a one off house - walking distance away from your bulk work) - fill a bottle of Fairy with your cleaning solution and use that to wet your applicator when needed.
Always change your rubbers every day, turning them at midday, to give a crisper edge to your squeegeeing. Less scrimming.
To climb over back gardens where the fence/gate is by the gable end wall; split your double extensions into singles. Place one single over the gate, against the wall; place your other on 'your' side of the gate. Walk up, step across and walk down. Retrieve your ladders and work as usuall.
Phone customers the night before to ask them to leave their gates open.
Carry your ladder mats/ladder stopper in your bucket of water - it saves going back to the van when you need them.
Microfibre are brilliant for leaded windows - don't squeegie. Just wipe over with a damp cloth and polish with microfibre.
Avoid taking on houses with leaded windows.
You can cut down or buy cut down squeegie blades for Georgian windows, but the damp cloth, dry cloth tecnique is faster.
Avoid taking on houses with Georgian windows.
When there's a few of you working from one bucket of water - save the water by dipping and rinsing your applicator - but then use one hand to run the length of the applicator, gently squeezing most of the water back into the bucket. I only do this with gloves as the green stuff wrecks my hands. Pour any remaining water from your bucket in a belt back in the main bucket. At the end of the day, pour the sludge out and refill with clean water.
Frosted glass - just rub it with a damp scrim - unless it's an upstairs bathroom window. (Leave it - but don't say I said so - you'll get a digging on this forum).