It depends on your definition of "success. Typically, this event type is great for building brand awareness/name recognition. Depending on the additional opportunities from the event host, you may want to consider to broaden your reach. You may also want to consider issuing and releasing a press release online, to your existing clients, prospective clients, local paper, trade journals, etc. A hook could be something educational/fresh/unique that you will have knowledge/expertise on. PMRNC's post re: compliance is a good one. Perhaps your "give away" could be a compliance checklist or similar.