Two students exchange drafts in class. If another response is needed, the pair can pass it on to another student. Two students read their drafts to each other and give oral comments in response. This form of response works well in large lecture sections. Students exchange drafts in class and e-mail a response.
Students naturally know how to respond to each other's writing.
Students need to receive pointed advice about how to productively respond to their peers' writing. Discuss the ground rules for effective response to a draft. You might also create a list of questions tailor-made for each assignment. After the role play, discuss which of the comments were most useful and which comments seemed vague, unclear, and less useful. You might put the procedure for the day's peer review on overhead while they respond.