If you are advertising eg yellow pages that would help - I missed the deadline and am still kicking myself - but get yourself on yell.com - you can have a free entry though they will try to sell you space
I am at the early stages of the commercial side - you have to be proactive - contact local authorities and different companies - get on their tendering lists
Also I pick, at random, a category from yellow pages or yell.com eg old folks homes and just ring em all -
Drive round and look for filthy buildings and phone them up - don't take a negative answer form joe bloggs who happens to be nearest the phone - get the person who deals with the window cleaning contract
Just a few ideas - good luck