It might be worth trying to talk to any of the groups that attended the events last year to see what worked for them, and perhaps more importantly what didn’t work as well. I also think it is important to work out in advance what you would ideally want from the event – is it about networking, raising your profile, donations etc. as that will give you a benchmark to work out whether or not it was successful.
One of the challenges it getting people’s attention so that you can engage with them
Best of luck with your events