We put four lunch tables in a square and sit on the outside. This accomodates at least 20 people. If we (ever) had more they could pull up chairs and squeeze in. The exec board trys to spread out so that we aren't all sitting together.
You can place the tables perpendicular or slanted towards the speaker, but only have chairs on 3 sides.
A couple of the places we meet (library, staff lounge) have round tables with 4 chairs, about 6 or 7 tables.
We just pull the chairs around to the exterior end of the table so none have their back to what's going on. Or if that's too tight, take those chairs and just move them to the perimeter. So not everyone is at a table, but that's okay.
We sit in the library and all the tables are round. I always hated sitting at a head table so now I just sit with the exec. board in the middle up front. Every turns their chairs and faces me. Seems cozy and warm.
What is the best way to set up tables at a meeting for 20-30 people. "U" shape can leave backs towards each other but if we set it up with tables grouped together (rectangle), we get too far away from each other to hear. I realize this is a good problem as attendance is at a all time high this year!