Do whatever you can. I'm assuming you are going after pros and hobbiests? I don't know if there is a big market in your area for rental studios to professionals (I know there is a big pro photo community in Seattle) but I would make up a promo card (maybe 5"x8") with a small shot or two of the studio, and some basic specs, and post it at every photo lab (custom and one-hour), camera store, appliance store (whereever cameras are sold) and college in your area. Also look to see if ASMP (asmp.org) has a local chapter, or PPA for that matter, and see what's involved in getting an ad in whatever they hand out or email out to members. Some groups raise funds by putting ads in their emails to local members. Also, if any of these groups do seminars and/or workshops, guest speakers, etc, they're often looking for a place to do them. If your space is big enough, offer it to them in exchange for 2 or 3 minutes to plug your rentals and hand out a promo card. In fact, if you think it would work, you could make it available to ANY organization needing a free space for a meeting, just as long as you get your commercial in, and its a group that might actually produce a rental. (A women's reading club might not produce many renters). You could also make it available for art gallery openings.
You could offer classes on photography, or workshops. Are you qualified to teach? Do you know someone who is? Could you bring in someone like Rolando to do a workshop? Aside from getting some revenue from the event itself, some of the attendees might turn out to be customers. If you have a list of available models handy, that would help too (be sure to include that item on your promo card - the local hobbiests will like that).
Finally, you could try advertising in the local paper, or college papers. Put a sign in the window of your car and park it near a shopping mall on Saturday or Sunday! Do whatever you can. That's all I can think of for the moment.
Regards,
Andy Pearlman
Andy Pearlman Studio