Hearing is simply the act of perceiving sound by the ear. If you are not hearing-impaired, hearing simply happens. Listening, however, is something you consciously choose to do. Listening requires concentration so that your brain processes meaning from words and sentences.
People who do not listen are one of my pet hates. After speaking to someone I sometimes find people staring at me and when I ask for their opinion they say what did you say? The other person is the one who listens to answer so they are not listening to the entire story.
I have found that to keep eye contact is important and to ask for feedback regularly through the conversation helps people to stay engaged. However, I do still find that some people just hear you and feel that by asking questions, no matter how relevant, makes them feel part of the conversation.
I would be most interested to hear what your experience has been with people not listening to you.