Several techniques need little preparation and work across disciplines. Think-pair-share: pose a question, give students a minute to think and write, then have them compare with a neighbor before a full-class discussion. Quick writes: a two-minute written response that gets every student reasoning, not just the fastest hand. Retrieval practice: a low-stakes question on prior material at the start of class, which strengthens memory far more than rereading.

Start with one. Adding a single well-placed active moment to a class period is a bigger improvement than overhauling everything at once.