Paint patterns or use peel-and-stick decals to add color to the walls. For example, bright pink and orange circles or neon-bright flowers instantly brightens up your black walls.
Place white furniture against the walls to "pop" against the black, especially large pieces, such as bookcase headboards, bookshelves or large chests. Hang a series of floating shelves on the wall in white or another light color if large pieces of furniture aren't an option.
Hang large, colorful pieces of art, framed posters or collages on the walls. Paint your own pictures on poster board if you can't purchase new artwork. Bright white or shiny silver frames contrast with the black walls, drawing your eyes to the artwork.
Cover the walls with curtains or fabric, such as sheer white panels, that allow you to pull back the material if you want a calming, dark space to sleep, but covers the black walls with light or bright colors when you want to be creative.
Use mirrors to bounce any light, such as from track lights or a window, to instantly brighten the room.
Include multiple sources of light to brighten the room when you want to read, entertain or be creative, as the black walls absorb the light. Use bedside lamps, track lighting, floor lamps, strings of miniature lights or any other lights that complement your decor.