The STAR approach is something that you can keep in mind when responding to a question. It defines a few things which will help you give a full and meaningful response to what an interviewer is asking you.
S/T: Situation or Task - Describe the situation that you were in or what you needed to accomplish. You must describe a specific event or situation, not a generalised response. Be sure to give enough detail for the interviewer to understand the specifics of your example. Where possible, the situation should be from a previous job.
A: Action - Describe the action you took and be sure to keep the focus on you. Even if you are discussing a group project or effort, describe what you did - not the efforts of the team. Don’t explain what you might do or should do, but rather what you did do.
R: Result - What was the result of your action? What happened? How did the project/ task end up? What did you accomplish? What did you learn?