All universities are concerned with students earning D's, F's, or withdrawing (DFW) from their courses, particularly in STEM and gateway courses. One way to reduce this rate is to improve the instructional practices in a course by introducing learning strategies, including spaced and interleaved retrieval practice in formative assessments. U-behavior, a learning and teaching method that includes a formative assessment to help guide students into optimal spaced and interleaved retrieval practice, was implemented in a course with a high DFW rate. In part, this method requires students to complete practice questions as a part of their retrieval practice. This paper describes how practice questions were developed to enhance students' retrieval practice using the U-behavior method, aiming to reduce the overall DFW rate. Data was gathered at the end of the semester and compared to previous semesters to better understand the impact of this effort. The data showed an overall reduction of the DFW rate by 14.7%. Additionally, students who spaced and interleaved at the highest level showed significant improvement on their final exam, suggesting the potential benefits of improving student performance.