The above video gives you a nice guideline for when forming teams. It explains some of the team models, and what type of team works best depending on the purpose of learning.
Robert Marzano, Debra Pickering, and Jane Pollock explain in “Classroom Instruction That Works” that effective learning in groups must have at least the following elements:
Collaborative teams can be either homogeneous or heterogeneous in their makeup. Homogeneous means “of the same kind or alike”, so students with similar English levels are grouped together. Heterogeneous means “diverse”, so in this scenario, student language levels would be mixed.
Targeted team instruction
In this group model, the instructor targets groups while the rest of the class works on the same or different activities. Targeting teams allows the instructor to give personalized attention to each group, and work with them on areas that may need improvement.
Using a station rotation model can be beneficial for certain activities in class. For instance, each station can have a different activity, and the class rotates through each one. The instructor can then circulate, or stay at one station to target instruction on the key lesson.
Identify the purpose of learning when forming teams
Before forming groups for class, we first need to identify the purpose of learning. It depends on the activity and the goal of the teacher.
Homogeneous groups are best to help medium and strong students gain higher learning, while heterogeneous groupings are ideal for helping struggling students.
3A Homogeneous team activity examples:
3A Heterogeneous team activity examples: