It depends on whether or not you want the space to be functional or decorative. If functional, then decide what you need additional space for and then draw out a plan, If decorative, decide on what your theme is for the room and buy/arrange items using that theme (which could be based on other furniture, color, hobbies, collections, the sky's the limit). I would collect photos or images from magazines/books that attract your attention and use this as your starting off point. Keep eliminating images until you select your top 2 or 3 and then begin to put your idea into action.
One thing to consider----- "dead" space can be as important as "filled" space.....not all empty space is bad.
Is it outside or inside? Makes a big difference!!
Look for a nice 5 or 6 foot corner cabinet.
Are you asking about dead corner space in a room? Or on a countertop? Or in cabinets?
closed off, two cabinets meet at corner
A large plant. A small table. A corner shelf. A larger table angled across the corner. A cat condo. A doggie bed or kennel.