Simple,
Cold call! Lots of it.
Visit them in person.
Drop off your details. like a small brochure, cards
We have alot of commercial work in CC, Office Cleaning, Window cleaning and more. We find that offices dont need CC that much. So you have to look at the otherside of the commercial sectors like nursing homes, retail shops as they need it clean for customer presentation.
Try to offer maintenance rather than a one off.
Office tend to have then cleaned if they are movin g in or out or they may have there entrance cleaned, foyer area cleaned.
Others may have better advice.
Dave