Organizing any meetup can be a huge undertaking for someone: extra stress, time and responsibilities. Hopefully this post helps you with your own event by covering my process for setting up CodePen Chicago: recon, promotion, event day, and closure. You can find more CodePen meetup info on Github, CodePen Meetups, feel free to contribute with any updates or fork for your own needs :D Here's a Trello board checklist, CodePen meetup.
During promotion mention all the benefits of the event space: accessibility, food, beverages, childcare, special guests, parking, location and etc. Review content for promotion with sponsors, co-organizers, presenters and those you feel could be impacted by the messaging. Give credit where it's due, if someone has secured a sponsorship, space or presenting make sure to give them credit for helping.
Send a reminder email the day of the event and if there's a cut off day for the RSVP list required because of building security. I arrive 30 minutes before start time to confirm wifi access, setup the equipment and test the AV. Make sure the space is accessible, food restrictions/allergies are accommodated, enough garbage cans for easier clean up and signage directing anyone to the space. Using the same computer is useful for tracking the presenters through browser history and if you are presenting from a pro account, you can use presentation mode. Allow everyone to get settled, 15-30 minutes from start time. Photograph, document the presenters and audience with a recap of the event. I encourage new presenters with some of the sweet swag, remember always be positive and encouraging, make it an inclusive space.
Write up a post with the event, presenters, photos and thank yous, you can find examples of other CodePen meetup posts if you need some inspiration. Make sure to promote it on Twitter and an email list, you can collect that through attendees when using nvite.com. Remember let there be code, fun and friendship :D