As the teacher, you know that no two students are the same, and no two classes are the same. Encourage everyone to participate. Offer positive feedback when each student is in front of the class. If you have someone that refuses, pull them aside and find out why. Each year, you will probably have at least one student who is uncomfortable with presenting to the class, and there are a few strategies offered by veteran teachers that can help encourage these students.
Be consistent. Presentations should be given at the end of each activity.
Make your expectations clear. Student’s need to know what’s expected of them.
If several of your students seem resistant, here are some teacher-tested strategies:
Consider starting out in pairs and working up to larger groups. The more students in a group, the easier it is for someone to hide in the background.
Assign each group member a task, such as recorder, reader, someone to maintain group focus, etc.
You can ask each student to maintain the work and solutions independently in a notebook or the textbook, and check them for a grade periodically.
Give out only one paper so that everyone in the group has to be focused on one paper
Have one person from each group present, but call on others to explain. When the students ask you a question, focus the question back to the group: "What does the group think?"
Try breaking the assignments up into smaller sections with more frequent reporting.
The teacher can only expect and encourage students to work together, but it’s important to keep the pressure on and keep your expectations high. Be creative! Have fun with it, and student success will follow.