Active listening is listening with all senses. That means giving full attention, honing in on non-verbals, and hearing the message of the person whether you agree with him or not. Asking yourself "what is the message this person wants me to know?"
Active listening doesn't come naturally, so we need to practice. My firm provides opportunity to do so by helping parties communicate effectively during mediations using active listening as the other important part of effective communication. Nothing worse than a talker/non-listener!