Be open to suggestions. You need not incorporate every suggestion your group makes in your revision of the draft, but you should make sure you at least understand their comments and concerns. If you don't understand what your group members are saying about your draft, ask them to clarify or give you an example. Follow along as the draft is being read, paying special attention to the concerns the writer has explained. Take notes directly on the draft copy, circling or underlining sections you find confusing or have questions about, so that you can specifically refer to them in your discussion.
Constructive criticism includes positive and negative components.
Use the Editor's Comment Sheet as a guide to structuring your comments. Begin with positive reinforcement. What is working well in the paper is extremely important. The author deserves to know whether she or he is on the right track, and to have a context in which to understand your suggestions for improvement. It is, on the other hand, unfair not to tell the author how to improve the piece.