While success rates are high in my calculus II courses (85-95%, depending on the semester), students struggle with integrating. In spring 2008, students were required to write "recipe cards" on integration techniques for trigonometric substitution and integrals involving trignometry. The average on the quiz was a 75%. Students presented their steps to the class and worked on these recipes as a group days before the quiz. In spring 2010, 2011, and 2012, I did not require students to create these cards; I highly recommended them, though. The quiz average dropped to 69% (2010), 68% (2011) , 61% and 54% (2012).
In Spring 2013, I decided to spend more time on the recipe cards. Students spent time in class developing them and working together with them. Less time was spent on doing actual problems in class. The quiz average was a 71%. Thus, from the results in 2008 and 2013, I will continue to require students to write these recipe cards.