try putting this post on the window cleaning section of this forum.
Speaking from my own experience I have had very little success with flyers. drop about 100 get about 6 jobs. Door knocking is usually the best way to build up a round. Make an effort in the appearance department and dont go for the hard sell just ask if they have or want a window cleaner. Get some cards printed, vista print will get you sorted there. If they have a cleaner already say thanks for your time and goodbye, maybe leave them a card incase they want a quote in the future. If they dont have a cleaner ask if they want a quote.
I am not advertising anywhere at the moment but the work is still coming in through word of mouth, and reccomendations.
Do a good job for a fair price and you cant really do wrong. Try to look professional, uniform or smart ish clothes
If you have the money to spend try roundbuilders. They will do the canvassing for you but they do charge.(not sure how much)
Good luck with it.
Ant
TVCS