Well, I've only done one, but happy to share what I did:

- Start collecting email addresses, see who might be interested. I just shouted it out on Twitter and got enough traction to realize we could gather at least a handful of people.
- Once you feel good about the list, pick a date, email everyone and ask if anyone would like to give a talk (if you want to present talks). Or give a talk yourself!
- Get a space for the event. Co-working spaces seem generally happy to host meetups, and they often have a projector and screen or at least a TV you can use.
- I was lucky enough to have a sponsor reach out who wanted to help pay for some of it, that helped a lot.
- Get food and drinks or at least a place with access to those things. I *way* over ordered assuming people were going to eat and drink more, but you live and you learn.

That's... basically it! People showed up, hung out, and were generally really happy to just be in the same room as each other. It was a really great time.