Perform a thorough research on the person you are interviewing before the interview. Gather information regarding personal and professional achievements, current occupation, hobbies or any other pertinent information that you can use as an introduction or description on your descriptive essay.
Call the person you intend to interview and set up a time and place for the interview. Keep in mind that the subject may want to conduct the interview in person or by phone. Be prepared for your interview several minutes earlier than scheduled. Have the questions you want to ask written down, as well as all the research you've collected.
Introduce yourself once your interview has started, and start out with small talk regarding the interviewee's hobbies and profession. Keep the conversation light and relaxed. Ask permission to record the interview session if you choose, but remember that a recording is not required. However, a recording will help you when you are writing your descriptive essay.
Ask each question thoroughly, and take notes as the interviewee is responding. Pay close attention to each answer, ask again if you don't understand the answer, but keep the interview flowing at a steady pace. Always ask open-ended questions in order to get a more elaborate response. Avoid any questions that the subject can answer with a simple yes or no. Remain congenial throughout the interview, and be certain to show appreciation when wrapping the conversation up.