I've only been going just over a year and found that word of mouth from my customers has got me 90% of my work. I had 2000 flyers made when i started and i've still got 1800 in my loft. Once i'd got a customer i ensured i did a really good clean including sills and frames....spoke to them professionally, had really good business cards made, they were pleased and i asked them to recommend me to one or two friends or neighbours, it was as simple as that. I now have a full round. Make sure your business card has your full name, address and landline, mobile and email address. People are far more trusting if they know everything about where you're from. A few other people have mentioned but this is a really important point. DON'T UNDERQUOTE JUST TO GET WORK. You will regret it in a couple of months. If you're more expensive than their last window cleaner explain to them that you are conscientious, hard working, never leave a mess, will turn up every month, polite etc, etc,etc. that is why you are a little bit more than the last guy was.