Mastery learning is a formative assessment strategy that involves the use of specific interventions, called correctives, to address the specific comprehension needs of the learner. Effective correctives are crucial for the effectiveness of mastery learning, so it is important that teachers make good decisions about what activities and strategies are used to address gaps in student knowledge. Correctives are defined as any instruction that present the concepts differently than originally presented, involve students in learning in different ways, and provide students with successful learning. Because of the time constraints inherent in the mastery learning process, not all instructional strategies can be used for correctives. The purpose of this review is to explore the available research and provide teachers the information to choose the most effective strategies and apply them in the most successful way. Tutoring, peer-tutoring, and cooperative learning are recommended for involvement strategies. Computer-based instruction, digital games, concept maps, and flashcards are explored as approaches to change presentation styles. Specific procedures for the appropriate ways and times to use each strategy are presented.