Hello matt,
I'll tell you what i have been doing to drum up my custom (as i am just starting) and it seems to work as the work i'm getting is coming in thick and fast.
I have been personally knocking on the doors of customers asking if they want my service, if they are interested and want me to come back the following month (just to make sure they not having you the once off) I offer to do their front windows there and then for nothing. Let's face it, 9 times out of ten you can tell the people who will genuinly want you to come back and the one's who are just going to waste your time and effort and not want you next month. I have a few more bit's and bobs i am tempting them with but as i try them i will post what the feedback is and let you know.
Hope this helps, Mikey