Have you ever had a conversation and you could see the other person wasn't listening to you? What they were really doing was waiting for you stop so they could tell whatever it was they feel is more important- which was them. They heard what you said but that isn't listening.
Listening isn't just hearing what is being said, its trying to understand the meaning behind why something is said. Often what someone says is not really what they mean or there are undying reasons that aren't being spoken. One time a counselor told my wife and I that when we talk we should relate back to the other person what we thought they meant. So I did and boy was I surprised. What I heard really wasn't what she meant. So when my wife tells me I am not paying attention, I now understand that what she really means is that I am making her fell like I don't value her because I am not hearing her. For me that was a turning point. I decided to actively try to understand rather than just hear. Not long after this I saw a video of a speech by the former president Bill Clinton. Politics aside , I noticed the guy had a habit of pausing after someone asked him a question before answering. Now I don't know if he was really trying to hear them or not, but the effect was that he appeared to be trying to listen closely. Not that Bill's a person I aspire to emulate but I thought it was a good impression and thought I would see the effect. When I am having an important conversation, I will often force myself to pause before I reply to give myself a moment to consider what is begin said. I found it helps me think about what they are saying really means. In my work I have found this very helpful and I think its why I can sometime figure out how to get to the bottom of an issue, figure out a solution or help cause an agreement to be reached. When I am listening to a group talk about why a particular thing at a restaurant doesn't work for them you have to get below to surface to understand why it doesn't work for them to get a solution. it often isn't so obvious.
Really listening isn't easy and takes some practice. Really understanding someone takes not just hearing but actively trying to get to the meaning of what is said.