Vague feedback and misinterpretation of writers' intentions on the reviewers' part have been found to be two major reasons why most of their comments are disregarded during writers' revision in one EFL writing class. To resolve this problem, a training was conducted to coach these students to generate more specific comments. Four characteristics of comments that were found to facilitate students' revisions in previous research were identified and used as guidelines during training: Clarifying writers' intentions, identifying problems, explaining the nature of problems, and making specific suggestions. Two teacher-student conferences with each reviewer were also held to provide individual assistance. Both quantitative and qualitative analyses of students' comments after training were conducted. Students were able to generate significantly more comments containing two or three afore-mentioned characteristics and were able to produce more relevant and specific comments on global issues. As reviewers, students benefited from this training in skill improvement, confidence build-up, language acquisition and metacognitive strategy use. As writers, they were able to approach topics of interest to them from multiple perspectives and to increase their vocabulary repertoire after training. (Contains 3 tables.)