Playtesting helps game designers evaluate not whether their games are useful and usable, but whether they are playful and playable. Strong playtest skills are critical to innovation in game design. They are also critical to making students self-directed, independent game designers who can evaluate and critique their own work. Better playtesting education is necessary if we want to help students create better games. We are developing and evaluating a workshop series to teach playtesting skills, as well as conducting research to understand designers' models of inquiry and iteration in the playtest process.