Listen, really listen, to what your partner (i.e. friend, lover, colleague, spouse) is saying. Listen so hard and so well, that you can repeat back to him or her not only the content of what they have said, but how they feel about it, too. Then do this! "Well, I heard you say that ___ is important to you, and that you really feel ___."
Listen with the ear of compassion, a silent welcoming. Not judgment. Not "yes, but..."
Listen with your whole body. Mindfully use your own body sensations and emotions to understand how you are experiencing this communication.
Listen to your own defensiveness, as the "yes, but..." thoughts begin to form.
Listen with patience, and without interruption.
Listen for the ways in which you can respond with gentleness and curiosity, rather than abruptly, aggressively, or dismissively. "Tell me more about..." or "Do you mean...?
Listen for the parts you can agree with, and speak to those first.