Andragogy refers to the method and practice of teaching adult learners. Some key principles of andragogy include that adult learners are self-directed, draw on life experiences for new learning, are ready to learn when they see a need, want skills applicable to real-world problems, and are motivated by factors like self-esteem. Adult learners learn best when instruction integrates past experience, uses concrete examples, incorporates various methods, and allows hands-on problem solving in an informal environment.