Here’s a great video by Dan “The Wolfman” Theodore on learning how to defend the clinch and then transitioning to a “wing chun” style knee pinch OR deadly arm bar.  The knee pinch to the opponents neck leaves them vulnerable to elbows and punches to the face.  Or you can transition from the clinch defense to an arm bar which can break your opponents elbow.  Check it out… a very clear and thorough example shown in this video: