Peer assessment is becoming more common across the curriculum. If it is to be effective, students need to know how to provide meaningful feedback. It is important to construct a rubric that draws students' attention to the important points of the work they are reviewing. But that is not enough; students also need instruction in how to provide comments that their peers can and will use in revising their work. This involves learning how to provide constructive suggestions. It also means understanding the way the author will react to the review, and using gentle enough terminology so that the words do not get in the way of understanding the reviewer's advice. Authors can also help reviewers learn the ropes by giving them feedback on the effectiveness of reviews of their work.