Remember the old suggestion box? If you're old enough to remember that, then you probably should take a seat and realize that feedback from employees on how you're doing, what they like and dislike about your organization, along with other matters, is paramount in today's workplace.
Short, handwritten notes really do the trick. They can be handed in anonymously without fanfare or fear of a loss of credibility. They also are much more dynamic, and believe it or not, better than email because they are direct in right in the face of any supervisor.
Also in vogue right now are handwritten evaluations of the supervisor. When was the last time you asked employees for this kind of feedback? If the answer is 'never,' then it's time to do so. Don't make the evaluation long - just a few questions will do nicely and will provide very immediate solutions on what supervisors can do to improve workflow, personality conflicts and much more.