Cultivating the ability to use multiple representations is considered very important in 21st-century education. Students should be able to employ not only verbal representations but also visual representations such as diagrams to enable effective organization, understanding, and communication of information. However, despite this acknowledged importance, instruction in diagram use is rarely provided to students. In this chapter, we describe methods we have developed for the provision of such instruction and refer to evidence for their effectiveness, not only in improving students’ spontaneity in using diagrams, but also in promoting deeper learning, communicative competencies, and critical thinking.