If you are confident enough door knock. I am not so I relied on leaflets and word of mouth (reputation goes a long way). When I started up I knew my job was going to go belly up in 12/18 months so I was in no rush to build it up fast. It did build up fast as I have a good reputation. I wipe the frames and cills every time. People love this and you will soon get people saying "my mum/sister/friend lives 5 mins away, can you do them to?"
I suppose I was lucky as most of the windys around me are crap.