Good luck on your upcoming event!
Push your fliers/announcements out to local universities and technical colleges, those are always a big source of attendees for us. Introduce yourself to faculty and department heads. We even had a masters degree program at LSU make attendance to our SQL Saturday a requirement of the program. We were able to advertise the event in junior- and senior-level computer science and Business Intelligence classes.
Contact your local TV and radio shows. I have made appearances on local morning "chat" TV and radio shows, something that really helped get the "SQL Saturday" brand out there. Also look at the local calendars of business reports, chambers of commerce, social magazines, and local business magazines. Proactively contact your local business/IT incubators, technology parks, training providers, recruiting companies to get the word out (and to sponsor, if they are not already!) Those kind of companies usually pride themselves on being "in tune" with the local IT industry.
Ask your speakers to blog about the event, especially if they are locals. Contact your local Microsoft PFE's (Premier Field Engineers) - they have local clients who will probably be interested and they can help you recruit attendees.
We actually don't have a lot of luck getting numbers of people on Facebook or G+ or LinkedIn to "join" or "I'm Attending!" an event listing, but wouldn't hurt to make sure you have events listed all over social networks.
Hit all the local user groups, not just the SQL
group but also the SharePoint and .Net groups and get their mailing lists
aware of your event.
Finally, be prepared for a lot of walk-up traffic. We have many folks walk in without per-registering each year. Road signs will pull people in, so many sure you get your signage up around major nearby thoroughfares early in the morning on Saturday. We print out 100+ blank name badges and raffle tickets to handle all the people who don't print SpeedPASS or don't register at all each year.
Whew, is that enough? Ha! Let me know if you have any questions, and good luck with your event!
