Choose remaining furniture pieces in a softer, more neutral tone such as white, cream or brown.
Accessorize the red sofa with pillows in a subdued pattern or color. Use a bolder pattern or red decorative pillow on other furniture pieces to create a balance among the furnishings.
Create a subtle backdrop for the furniture and accessories. Paint the walls in a neutral wall color such as a light gray or brown, or paint the walls a shade of white.
Accentuate substantial decorative pieces in black, such as the fireplace mantle or hearth or a grouping of photographs on the wall.