Cover the work area with drop cloths to help prevent paint from dripping onto the work surface. Center the sofa on the drop cloth so that all sides of the furniture can be easily reached.
Prepare the sofa for painting by cleaning the sofa. Vacuum the surface to remove any dirt and debris. Gently scrub the entire surface with a nail scrub brush to help loosen the fibers.
Paint the sofa using upholstery spray paint. Stand about 4 to 6 inches away from the surface of the sofa as you paint. Spray a thin, even coat of paint onto the surface. Keep the paint can moving in the same direction using long strokes for the best coverage. Allow the first coat of paint to dry to the touch.
Scrub down the surface of the sofa with the scrub brush before applying a second coat of spray paint. Paint in thin, even strokes as you did with the first coat.
Check the dry sofa to determine whether any touch-ups or a third coat of spray paint is needed. Look for areas missing paint or looking a little bare. Spray on another coat or touch up missing areas using the process described above.