Increased expectations for writing performance have created a need for formative writing assessments that will help middle school teachers better understand adolescents' grade-appropriate writing skills and monitor the progress of students with or at risk for writing disabilities. In this practice piece, we first explain research-based recommendations for high-quality writing prompts that are interesting to students, provide clear directions, and ensure accessibility and fairness. Then, we use lessons learned from working with adolescents in Tier 2 literacy intervention classes to demonstrate how teachers can apply the recommendations to identify or develop prompts that will encourage students to write responses. In addition, we explain how analytic rubrics may be used to evaluate responses as a means of informing instruction and further refining the prompts. [For the corresponding grantee submission, see ED626658.]