We do a lot of apartment complex maintenance & repair work. To get it started we put together a list of all the types of things with could do to help them with upkeep, repairs etc. We sent our best communicator out with a list of Apartments and he would introduce himself to the resident manager and talk with them.
Some had authority to hire for work up to a certain dollar amount, others referred us to a main office. We did this 2 or 3 days a week for a 6 months. It was slow going and was lots of red tape, forms etc. Little by little we were able to get enough that It kept a truck busy on a daily basis. Now we almost need 2 trucks for it, but not quite.
After you get in the door it gets easier. We make friends with their in house maintenance guys and they find us work so they have less to do.
Like Rewire said its typically 60-90 days to get paid.