Allow more light to enter the living room by using light curtains. Instead of using heavy looking "valances" use easy and if possible semi transparent curtains that are ample to reduce glare that might be caused because of direct sunlight. Use brighter color schemes commonly known as "hot" color schemes. These create a very good reflection and transmission of natural as well as artificial light inside the living room. You can find one more different strategy to defining the perception of the living room (or any interior space) and that's the empty volume put aside after all the furniture along with other accessories have been fitted. Because anything in our living world is obviously "relative". The perceived volume is always relative to the empty volume that is normally used for circulation. The more empty volume you get, the bigger the room will look.