Critical thinking is reasonable and logical thinking focused on deciding what to do or believe. A good critical thinker has the ability to rigorously understand and evaluate arguments and evidence, and to use these things to come to a reasoned judgment. This study deals with the Strategies of developing critical thinking skills to make careful judgments, make proper decisions, solve complex problems, analyzing arguments and assessing it, and wipe out the basic inability to communicate appropriately at the everyday life generally. This study lays the conceptual foundations necessary for understanding the mind, its functions, its natural propensity toward irrationality, and its capacity for rationality. It is designed for those interested in developing their potential to be fair-minded reasonable persons, concerned with how their behavior affects the lives of others, concerned to develop their full humanity, concerned with making the world a more civilized and just place. It is designed for those willing to transform their thinking to improve their decisions, the quality of their lives, the quality of their interpersonal relationships, and their vision of the world. This study is divided into six chapters preceded by an introduction as follows: Chapter One: Nature of Human Thinking Chapter Two: Basic Principles of Critical Thinking Chapter Three: Argument: its construction and analysis Chapter Four: Critical Thinking and Assessing Arguments Chapter Five: Logical Fallacies and Cognitive Biases Chapter Six: Critical Thinking in Everyday Life