In large formal groups: Robert's Rules of Order.

Large organizations, and organizations which have to remain unified despite bitter disagreements, developed social technologies such as RRoO. These typically feature meetings that have formal, pre-specified agendas plus a chairperson who is responsible for making sure each person has a chance to speak in an orderly fashion. Of course, RRoO are overkill for a small group with plenty of goodwill toward each other.

In small formal groups: Nonce agendas and rotating speakers

The best-organized small meetings I've ever attended were organized by the local anarchists. They were an independently-minded and fierce-willed bunch who did not much agree but who had common interests, which to my mind suggests that the method they used might be effectively adapted for use in LW meetups. They used the following method, sometimes with variations appropriate to the circumstances:

1. Before and after the formal part of the meeting is informal social time.
2. Call the meeting to order. Make any reminders the group needs and any explanatory announcements that newcomers would want to know, such as these rules.
3. Pass around a clipboard for people to write agenda items down. All that is needed are a few words identifying the topic. (People can add to the agenda later, too, if they think of something belatedly.)
4. Start with first agenda item. Discuss it (see below) until people are done with it. Then move on to the next agenda item. In discussing an agenda item, start with whoever added it to the agenda, and then proceed around the circle giving everyone a chance to talk.
5. Whoever's turn it is, they not only get to speak, but they are the temporary chairperson also. If it helps, they can have a "talking stick" or "hot potato" or some physical object reminding everyone that it's their turn. They can ask questions for others to answer without giving up the talking stick. If you want to interrupt the speaker, you can raise your hand and they can call on you without giving up the talking stick.
6. Any other necessary interruptions are handled by someone saying "point of order", briefly stating what they want, and the group votes on whether to do it.

In small informal groups: Natural leaders

Sometimes people have an aversion to groups that are structured in any manner they aren't already familiar and comfortable with. There's nothing wrong with that. You can approximate the above structure by having the more vocal members facilitate the conversation:

• Within a conversation on a topic, deliberately ask people who aren't as talkative what they think about the topic.
• When the conversation winds down on a topic, deliberately ask someone what's on their mind. Be sure to let everyone have a chance.
• Tactfully interrupt people who are too fond of their own voices, and attempt to pass the speaker-role to someone else.