The Rule of Group Dynamics is a great principle to bring into any facilitation to make space for quiet people and give permission to check the process. It states that, if you're thinking something, feeling something, or if you have a concern, chances are at least one other person is thinking the same thing. So, speak up. Say what you're feeling. Ask questions. Make requests. And we'll deal with it openly as a group.
I first heard the Rule of Group Dynamics from Elise Yanker.