This document seeks to present knowledge about the students, the learning process, and mainly about classroom instruction to both current and future teachers. Teaching is one of the important jobs where the teacher plays the roles of: a leader, an effective speaker, a quick diagnostician, a tactful diplomat, and a firm but fair disciplinarian. Teachers have to be "on" all the time and they do not leave their jobs behind when they go home at the end of the day. Good teachers know their subject matter and have mastered pedagogical skills. They accomplish all the tasks involved in effective instruction with warmth, enthusiasm, and caring. Good teachers are also critical thinkers and self-regulated and use educational psychology¿s principles when making a decision and when teaching. They combine research and common sense. In the same sense; the field of educational psychology is the systematic study of learners, learning, and teaching. It focuses on the processes by which information, skills, values, and attitudes are communicated between teachers and students in the classroom and on applications of the principles of psychology to instructional practices.