For the last 9 months I have co-organised and presented Machine Learning Dublin , a meetup group started by ADAPT Centre that rapidly grew from 0 to 1350 members. Now that I have stepped back, I want to share ten lessons that I learned through this wonderful experience. Form a great team. The effort to organise a meetup is largely underestimated: it can easily take you 30 hours per event. Make sure you have a good team of at least 4 people and assign responsibilities: finding speakers, sponsors and venues, presenting, managing website and social media, registration desk, etc. Secure great venues. The event space plays a fundamental role in the success or failure of a meetup. Secure nice-looking event spaces in the city centre that are easy to find by the attendees. Some topic-related companies, startup incubators and co-working spaces might offer their facilities for free. Be picky about speakers. Select 2 or 3 good speakers per event that engage...