Self-directed learning allows students to take responsibility for planning, implementing, and evaluating their own learning. It involves a continual process of self-motivation, self-management, self-monitoring, and self-modification. Successful self-directed learners have skills like goal setting, decision making, self-awareness, and content competence. While it has advantages like enhancing thinking and promoting independence, self-directed learning also has disadvantages such as being time consuming and potentially misguiding students.