I recommend that in most cases you require students to write down clear notes or points they wish to cover during the group meeting. Any materials or illustrations also should be assembled in advance. This way, when the group comes together, the time is spent productively. Because you will typically have three students in a group, you will have to make it clear that each person should be given equal time to present. Of course, you should allow a few minutes for each group to converse informally, a sort of “warmup” time, and you should allow time at the conclusion of the presentations for the group to do some reflective thinking about what they have learned.