I saw Mark Cuban speak at the CNBC/Inc. Chicago Iconic conference last month. He shared several awesome pieces of advice and was very candid with his answers, but one of his responses stuck out in my mind as the most powerful.

Cuban worked with a mentor early in his career that was enamored with Cuban’s enthusiasm, but felt that Cuban needed more focus, especially in meetings. He told Cuban that anytime they started a meeting, Cuban was to write the word LISTEN at the top of his notebook and reference it throughout their time together.

This gentle reminder focused Cuban’s energy and he follows this advice even today. Every time he sits down for a meeting or to listen to a pitch–he writes the word LISTEN at the top of his page.

When you consider listening, it’s more than being quiet and waiting for your time to talk. Listening involves asking probing follow-up questions to clarify that you understand what you have heard. You must listen to your customers to build products, services and solutions that fit their needs. You must listen to your employees to learn how best to motivate and lead them.

Listening is an essential part of effective communication.

So the next time you watch Shark Tank and see Cuban writing in his notebook, imagine him writing the word LISTEN. Pay attention to how he questions the entrepreneurs. Learning how to listen is a key to entrepreneurial success.