Chances are, someone has voiced their opinion about your personality. Most likely, you have opinions about the people you know. Understanding how the elements of your personality interact with others is key to recognizing types. The Myers Briggs Type Indicator is a heavily researched personality inventory used by corporations, schools, and community groups. Through observation and direct questioning, you can begin to recognize personality types with relative effectiveness.
Engage with the person by recognizing the introvert/extrovert scale. Introverts refuel by finding time alone and prefer small group interaction or solo work. Extroverts refuel by engaging with groups of people and prefer being a part of the action.
Understand how the person processes information by recognizing the sensing/intuition scale. Sensing people utilize their senses -- touch, taste, smell, sight, feel -- and process information based upon past experience. Intuitive people utilize thematic connections and process information based upon possibility and hunch.
Recognize how the person judges the world and makes decisions by recognizing the thinking/feeling scale. Thinking people are objective in their information intake and weigh situations based upon fact, research, and data. Feeling people are subjective in their information intake and weigh situations based upon how relationships will be impacted and how things feel.
Relate to how the person organizes their life by recognizing the judging/perceiving scale. Judging people are the organized, everything in its place, and on-time type of people. They develop consistent processes for solving problems. Perceiving people are more fluid, roll with the punches and are less likely to be consistent with their organizational style. They are more likely to go with the flow.