Rule 1: Spend as much time on logistics as on content
Most events run by amateurs are “amateur” because they fall down on details. They have a great idea, or a great speaker, but the event turns out mediocre because the sound system doesn’t work or because there’s no parking nearby. It’s more fun to focus on the big stuff, but getting the little stuff wrong will kill you just as dead as getting the big stuff wrong.
Overall a very good refresher on the things to pay attention to when trying to run public events, especially handy if you are involved in local groups doing community outreach.