Just keep radiating outwards from your home, keep knocking doors, keep delivering leaflets, and keep smiling
Make sure you leave a leaflet with everyone you canvas, they may not want you now, but they might in the future.
The more 'in the sticks' the fewer window cleaners will be around, but you will be viewed with suspicion
There are always plenty of gaps in the market, you may only pick up 1 account in an entire estate, but by the time you have cleaned it a few times you may have picked up a dozen more, half the time, all it takes is a toehold, people will see you turn up every month and then come to you.
I hate and detest knocking on doors, people hate salesmen calling, a tip I was told by a door to door salesman was to knock on the door and be starting to walk away as they answer the door.
As you walk the couple of paces back to them, you can at least have the chance to explain who and what you are, if they don't want your services, you can at least leave them your flyer and card and tell them you will be there should they change their minds.
And have you noticed how: If the husband answers the door and shouts back in to the house to ask the wife if she wants a window cleaner, the answer that comes back is invariably no
Try and talk to the woman of the house, the men are toss pots
I agree with all that Jon said too.
Ian