The authors share twelve practical tips on writing a case that engages learners in active learning and discussion. They first advise that, during the initial preparation of the case, authors should (1) identify the case goals and objectives, and (2) identify the level of the learners. When writing the case, authors should (3) use active and colorful language; (4) use patients' own descriptions rather than medical language; (5) allow the learners to interpret data themselves; (6) allow for natural discovery rather than presenting information chronologically; and (7) be realistic about interruptions in patient care. In addition, case authors should pay attention to methods that enhance discussion by (8) creating barriers to diagnostic or treatment options; (9) promoting questions and discussion over answers; (10) using cues to assure discussion flow and knowledge exploration; and (11) omitting details or inserting informational distractors. Finally, well-crafted questions are essential during the case presentation to engage learners in higher-order thinking; and to (12) stimulate curiosity and reflection.