Use of the room. Relation of rooms to each other. Rooms that are open to one another are more pleasing if color schemes are related. Adjoining rooms are more attractive if colors are repeated from one room to another. Size of house.
Small houses look more spacious if one major color dominates throughout.
Combining the new with the old. Be careful when choosing new things to go with older ones. Time and use soften colors and textures. If new things look brighter and fresher they can make older furnishings appear soiled and worn. Organization of space and furniture.