The historic underrepresentation of women, certain racial and ethnic minorities, and members of other marginalized groups in careers in science, technology, engineering, and mathematics (STEM) reflects a disproportionate exit of individuals from these academic and career paths due to both environmental and personal factors. To transition successfully from classroom-based learning to the research environment, students must acquire various forms of capital nested within a largely hidden curriculum that most scientists learn informally. We have developed a semester-long course for undergraduate researchers that makes explicit concepts and strategies that contribute to STEM persistence. The course teaches skills for: (1) scientific communication; (2) maximizing the effectiveness of research mentoring relationships; and (3) navigating scientific culture and its interactions with multiple social identities. We offered the course for three consecutive semesters at the University of Massachusetts Boston to 33 students from different backgrounds, academic majors, and educational experiences. Quantitative and qualitative assessments demonstrated student learning in all three areas of emphasis. By deliberately combining instruction and practice in skills, such as those needed to present and critique scientific research, with skills needed to optimize personal interactions and key research relationships, we have created a novel learning experience to promote persistence in STEM.