Supporting students' in-the-moment perseverance is a vital objective in mathematics education because it promotes learning with understanding. Yet, little is written about if and how student perseverance can improve over time. I examine the specific ways in which secondary students improved their perseverance as they engaged with challenging mathematical tasks over six weeks. The results show that encouraging students to initially attend to their conceptual thinking can prolong productive effort upon impasse and explicitly improve selection of problem-solving strategies and affect regulation. These findings suggest learning environment designs that provide consistent opportunities for students to practice (and improve) their perseverance. [For the complete proceedings, see ED606556.]