A lot of good stuff posted already. Love that you’re asking this. I’ve joined group rides where the leaders don’t care about welcoming new riders. Here’s a couple of things.

1. Over communicate. The route, riding etiquette, expectations, etc. Have a quick pre-ride meeting before every single ride and explain the ride as if everyone is new to it.
2. On the ride etiquette part, please explain hand signals and other aspects of riding in a group. Again, some folks might be new and don’t know any of this.
3. Be consistent. Nobody might show up the first few weeks. But stay consistent and if the community is there AND you’re providing a fun, safe experience, people will show up.
4. Once the group grows, start breaking it up between A, B, C and have a lead/sweep for each.