I "specialize"(if there is such a thing) in apartments and I have a whole bunch of fliers made up (with my basic cleaning list, ball-park quote and my phone number) and I take them to the apartment manager's building and leave them 50-100 (depending on size of complex) and have them put them in their welcome packets. I've gotten a lot of business that way. Managers are more than happy to refer cleaning people to their tenants!
I have fliers and business cards on me always and I give them to anyone who has a pulse. I say "I own a cleaning company in town and I'm very reasonable, so if you know of anyone looking for help cleaning...." I've never had anyone be rude to me. (I'm bubbly) I was at a flower shop today and the person working there took 10 fliers from me and posted them in his dorm at college (don't know if that was good or not...but it's a contact!)
The other thing I do, is I'll text, call, or fax someone I know (so I kinda know what their house looks like) and say "I need a house to clean on Tuesday. $80 and I'm yours." It's funny (I hope) and at least gets a chuckle and makes people think of me.
I put my fliers and cards up everywhere I shop (the mileage there is a tax right off and I'm going there anyway)
I don't know if you can use any of those ideas, but that's what I got!