This is probably what I'm asked most often. What do you do when someone just takes over, or constantly comments without allowing anyone else to talk? My best solution is exactly what I do with students...deflect, derail, and dissolve. First, deflect an off-topic comment or a comment that is designed to inflame the group. "That's really interesting. Since we don't have time to discuss that fully today, would you mind just writing it down on a post-it and we can come back to that at a later time." Or...."That's an interesting topic. Why don't you do some research and then come back to me with that later and we'll plan a time to include it." By the way, that one is perfect for students who want to draw you off topic--they get extra homework as a bonus!
Next, derail. Often, the person is looking for attention. So let's find a way to shift the attention away. I immediately ask people to grab a partner and discuss something. Then I can go over, and speak to the person individually.
Finally, dissolve the issue. People who want to grab and keep attention are masters at it when you are asking the whole group a question and then asking one person to respond. Include lots of pair-shares, small groups of three to discuss and share out, etc. One of my favorites with a group is to allow small groups to discuss, then have the pick the person who has talked the most during the session. That person is the notetaker. Then, they pick the person who has talked the least, and they share the group's response. A fun way to solve the problem.
Enjoy your weekend, take some time for yourself. I'll be in Houston Monday working with some great teachers in Pearland. I know I'll have a great time!