Is your desk too small for the stuff that sits on top of it? Are you feeling cramped and penned in by hot files, current files, your computer and just the mere presence of your coffee cup?
Whenever possible, move to vertical storage and even a vertical desk. what? Put my desk on the wall?
Pretty much, that’s it. consider placing shelving units above your desk or, if space does not permit, even to one side of your desk. Then set up the items off your desk onto the shelves. Those things you use daily will be closest to you while the occasional items can sit on the shelves farther away.