Hello Bart,
I was in property management several years ago. Here are some things I did that really helped increase the occupancy rate. Not sure where you are located which might make a difference but these may work anywhere.
Yes, call your section 8 and local Rural Development offices, let them know you have vacancies, send them your contact info and make a note to call them at least once a month. Also remember to be courteous to them and if you do get full, tell them that as well.
Go talk to your local chamber of commerce office as well as the library and any other local office you can think of where people who are moving to your town go to for information. Leave some cards with them. There are a lot of people moving around the country right now. With the housing market as it is many people are renting in an area before they buy. They want to see what the local market is doing before they decide to buy. These folks usually make great tenants too.
Look and see if people are moving to your area primarily from one or two other states. (you can talk to a few Realtors and find out the current trends there) then maybe put an add in some news papers or web boards in that state. Get their attention before they even get to your area. This can be an added service by offering a short term lease. Then they will refer your complex to their friends and family who will inevitability be following them to your state.
Hope that gives you some ideas and helps. :)