Nothing says "hire me" better than a track record of achieving amazing results in past jobs, so don't be shy when answering this question! A great way to do so is by using the S-T-A-R method: Set up the situation and the task that you were required to complete to provide the interviewer with background context (e.g., "In my last job as a junior analyst, it was my role to manage the invoicing process"), but spend the bulk of your time describing what you actually did (the action) and what you achieved (the result). For example, "In one month, I streamlined the process, which saved my group 10 man-hours each month and reduced errors on invoices by 25%."