Bulletin boards with yellowing cartoons and announcements of events long past also contribute to the overall messy appearance of a work station. Arrange your tools and materials for the work to flow efficiently through your work station. Your arrangement might not be quite the same as another person would choose because your methods of working are slightly different. Place frequently used items near at hand. Use lower priority space for other items.
Some people work more comfortably with all projects and materials out in plain sight.
Others like to have everything stored away except what they are working on at the moment. Arrange your work station the way you like to work - within the bounds of safety and University policy. Have a place for everything, and return it to that place as soon as you are finished with it. But have no more items than you need in your work area. Surroundings free of clutter help you think more clearly.