First remove, rearrange and re-accessorize. De-clutter is the best first step along with de-personalizing. New accessories to draw the eye to a great focal point of the room and possibly add an accessory that does not work in a different room.
Secondly, create a clean homey feel possibly with fresh paint or adding a a new light fixture. Mirrors are great additions to give the illusion of a larger room.
Third, Freshen up an out dated room. Budget allowing possibly new kitchen cabinets and counters.