Once your group starts attracting more members, get to know them! Welcome them personally to your group. Learn their names. Some of them would probably be open to speaking or hosting an event for the group. One of our first speaker events was hosted by a local member, Jim Lassiter on “Myths About Evolution and Secularism.”
Schedule weekly and/or monthly events for the group, such as lunches and dinners. We had regularly scheduled social gatherings where we had up to 20 people in attendance at our lunches and dinners.
One tradition I started for the group was to have an annual Winter Solstice Party. The first two were held at our house and each year we had about 40 people attend. It was a great time! Everyone brought a potluck dish to share and the casual party provided us lots of opportunities to converse, meet new people, and celebrate the Winter Solstice together.
Another idea for a party is a “Star Party.” Since we own quite a few telescopes, we hosted a party for the group and we set the telescopes up in the backyard and we were able to see Saturn, Jupiter, the Moon, and several star clusters and constellations.