Easy to learn Active Listening, harder to practice.

The idea of active listening can be learned in a few hours, but it will take a long time to put it into practice, because people can't easily change their habit of communication.
You'll need to remind yourself each time you talk to your boss (or your coworkers, kids, etc) that you want to practice active listening, and do one specific thing, like restating what you have just heard. After a while, it becomes a new habit, and you gain the skill of active listening. Just do it:-)