The STAR method

Every behavioral answer has the same job. The interviewer needs to know what happened, what you did, and what changed because of it. STAR is a way of covering all three without leaving anything out.

STAR stands for Situation, Task, Action, and Result.

It is not a script, and you should not announce the parts out loud in the interview. It is a checklist you run against your own story beforehand, to find the part you would otherwise skip. Most people skip the same two: the Task, which is what you specifically were responsible for, and the Result, which is what actually changed.