In all my teaching jobs, I have found myself responsible for an inordinate number of keys. One for my room, one for the music storage room or closet, one for the auditorium, and sometimes even more for practice rooms, other music rehearsal rooms, or the fine arts wing. Music teachers are almost always responsible for more than one space, and those spaces usually come with their own keys.
I recently got fed up with trying to remember which key was on which part of which key ring, and decided to label all of the keys so I could find the one I need more quickly. I knew exactly what I was going to use too: my trusty duct tape, of course!
Since I already had duct tape on hand in lots of different colors, I cut off a small piece and attached matching colors to the locks and their corresponding keys. It had made it so much easier to find the key I need right away, and of course it always makes me happy when I can add lots of colors to something I have to look at every day! :)