So many of us have become so accustomed to the 'noise' of life that we forget to listen to ourselves. We all sometimes eat for reasons other than hunger - boredom, being upset, to cheer ourselves up, to give us energy, to treat ourselves - and that is perfectly normal.
It only becomes problematic when the external cues take dominance over the internal ones. Do you really want food or would something else actually fulfill your need better?
The second part of listening to your body relates to when to stop eating: learn when you are satisfied and don't eat until you are uncomfortably full. Some people find it helpful to practice leaving something on their plate to break the habit of cleaning it completely. Do whatever works to help you listen more to the internal body.