Add three or four red and orange throw pillows to the couch immediately. This will instantly warm up the space, giving it a dose of color that complements the tones of the couch and contrasts nicely with the walls.
Add wooden chairs that are slightly lighter in color than the couch. The chairs should be upholstered in warm-toned fabric, such as cherry or burnt orange.
Place a patterned throw rug at the foot of the couch. It should have shades of brown, gray, red and orange to pull the entire palette together.
Hang framed wall art such as prints or paintings on the gray walls. The artwork can have any colors you like. The frames, however, should be gold to brighten up the walls.
Add patterned window treatments to your windows in one of your warm colors, such as red, orange or gold. A patterned fabric window treatment will give the space a more dynamic feel.