Just as it's nearly impossible to get anything done in an unorganized office, a disorderly exhibit is equally ineffective. So take a lesson from organizational professionals and enlist the help of a labeling system.
Start by labeling all of the small storage compartments in your exhibit, and indicating what goes in each of them. For example, label the outside of each drawer with a list of its contents, e.g., office supplies, staff schedules, breath mints, pens, etc. Then label large storage areas with names of the bulky items that tend to fit best within them.
Consider labeling various areas of the booth where small components are positioned most effectively. For example, if your card scanner is most often used near a product demonstration rather than at the reception desk, label a tabletop near the demo with the words "Card scanner goes here."
Not only will staff be able to quickly locate various items, but also the person charged with setting up your exhibit will easily be able to place all components during installation.