I have asked this question alot from other agents and have found there's no great secret to stand out from others. Just be you. Don't act fake or arrogant, just stay calm and be honest. If you don't know the answer to something, just tell them you'll find out and get back to them. Don't give a wrong answer and then have to back track later. It makes them question you and lose confidence in your abilities. Always smile and make them feel important. This is my advice.