Micro-teaching is a technique used to train teachers where they teach short lessons called micro-lessons to small groups of 5-10 students for 5-10 minutes. This allows teachers to practice specific skills in a controlled environment. The objectives are to help teachers learn new skills and gain confidence in teaching. Key aspects of micro-teaching include scaling down the lesson size, focusing on specific skills, providing feedback to teachers to improve, and repeating the process until skills are mastered.