Participation in the debate counts for 8 points of your grade, a small but significant contribution. It is also an opportunity to practice public speaking in a safe atmosphere -- to confront and overcome some of your fears of speaking, as well as to work on delivery and other communication basics.
In my assessment of your participation, I will not be focused on whether or not you stutter or say 'um' a lot'; this isn't a class in speaking. (It may be better to prepare for speaking by steeping yourself in the material.) I will be looking for evidence of careful research, thought, preparation, and honest efforts to "think onyour feet." I will not ask for or use your notes or other materials for this; my only evidence is what you say. Both quantity and quality of what you say will count.
Quantity: Each person should be sure to speak; I will be keeping track of it. Obviously the person who starts off with the summary will get that opportunity. After that, others have many chances to express their views: in the exchanges with the other team, and with the class as a whole. Since there is very limited time, panel members should be careful not to dominate. If your team is well prepared, you will know who is the best person to respond to a question, and give her or him that opportunity to talk.
Quality: Your team's key arguments should be touched on in the opening statement. It will be up to others on the team to develop them in more detail, as the questions and responses unfold. You will be best prepared if you have anticipated questions that other team is likely to raise, and if you have formulated central questions to pose to them. A question doesn't have to be a one-liner - you can demonstrate your preparation by carefully developing a crucial problem that you pose to the other team. A response doesn't have to 'win' by defeating; it is often as important to reframe an issue as to address it directly; both are important. The end result of the debate should be an elevated grasp of the main issues by the audience.
Material in the debates is part of the material of the class, and may be used in exams or papers. Audience members should fully engage themselves. I usually take extensive notes during the debates to help my memory and support the points I assign.
Debate panelists should conduct themselves with courtesy and consideration for all other panelists and class members. It may help to review the "Participation protocol" on the syllabus. Remember, what is being debated is positions and ideas; this is not about attacking persons. Moreover, our collective goal is learning -- ideally the debates will enlighten us on the issues. That can come about through articulation and analysis of disagreements, but repeating a deadlock probably doesn't help. Even while trying to put the best case for your 'side' forward you can be open to revising (even radically) your position. An attitude of thoughtful consideration makes it more likely that we will attain clarity on the nature and limits of the disagreements.