Peer-reviewed papers remain a source of high-quality reliable scientific information, especially valuable in the modern world. To help those who are starting to participate in peer-review, I discuss a number of questions related to this process. When should you say yes to an invitation to review? How do you write a report that is appreciated by the editors? How do you provide feedback to the authors that is fair, constructive, and helpful? What are the specific points that should be considered when analyzing the abstract, introduction, results, discussion, conclusion, and Supporting Information? How do you structure your report? How do you make the final recommendation? What ethical and diversity issues are involved?