You should conclude with a comment summarizing your feedback at the end of the piece. Like your students, you should approach this task as a writing situation: what is your purpose, who is your audience, and what do you want them to do with this information? Here are some best practices to help:
Address the student by name. The end comment should be written as conversation between you and the student, and like any conversation, should begin with greeting the student by name. This personalization shows the student that you are concerned about their progress as an individual student and not just a member of the class. It also shows that the feedback itself has been personalized for them rather than the more impersonal feedback from a rubric.
Use the ‘sandwich’ method. Like any writing situation, you want to engage your audience (not alienate them), so you should begin with on a positive note: “I can see you working to engage with the prompt.” or “This paragraph in particular is well-structured.” Then, provide the constructive feedback: “I would encourage you to use the prompt as an outline.” or “Consider this paragraph as model for your others.” Finally, end with resources available to help them further improve.
Identify and clearly describe two or three revision tasks, practice suggestions, or available resources. If students see a long paragraph that begins with negative feedback, they will be less likely to continue reading. Instead, use the ‘constructive’ part of the final comment to give two or three key points to focus on for the future, which will also work to reinforces that writing is process-driven rather than product-driven.
Sign off. Signing off (name or initials), your contact information, and office hours (time and location) is an important reminder that again, this feedback is part of a conversation about their writing and that students know you are encouraging this conversation to continue. Students feel more encouraged to ask questions knowing that you have personally invited them. The additional benefit for you is that it is a gentle reminder that you are a person (and not a grading robot!) right before they see their grade.