A first important thing to evaluate is the chairs and couches position. Ideally, they should be facing the door, or at least never with their backs towards it. People who are in feng shui living rooms should always be able to see the door from where they are sitting without having to turn for it. Seats should also be placed following a octagonal or circular shape.
Corners or dark areas should be lightening up through the use or combination of clear colors, plants, mirrors or light. That would attract chi to them which otherwise wouldn't flow through those areas. It is important that chi is able to flow through all the living room space, among the furniture and in the corners as well.