I’ve done a bunch of presentations, mostly to very small groups (10 or less). While this may seem inefficient, the most successful thing I’ve learned is to think about the audience and present specific examples that they can relate to. Land Trust or Refuge people like the idea of a continuously updated list of their biodiversity as a reference for reports, presentations and grant proposals. Nature nerds love the idea of using iNaturalist for scoping out great places to hike. Teachers want tips for the classroom. Researchers are excited that they can reach out to observers for pilot-project information or (within reason) seed collecting.
So the presentation is a very short slideshow about the two lobes of iNaturalist (database and social media) and then I switch to live pages (what is an observation, how you can use iNat) that I’ve stored as bookmark tabs for that audience. I’ve found they are often so engaged they want me to pull up more pages. And some turn out to be power users, which is very rewarding.