Making a room look larger involves several different decorating techniques working in unison. Some involve fooling the visitor's eye, while others involving changing the room's apparent perspective. It is amazing what mirrors, paint and windows can do to add a sense of depth to any room.
The first and perhaps most common fix for smaller rooms is the addition of mirrors. Affix mirrored glass panels to the wall opposite the entry way to a small room. The entire wall does not have to be covered in mirrors to be effective. A few panes placed at eye level can create the illusion of added space. Even a single large dresser mirror with frame can add depth to a room. The only real danger in using mirrors lies in overkill.
Having a large picture window can make a room seem bigger because a barrier between visitor and outside view has been removed. Instead of seeing a dimension-defining wall, visitors see an expansive view of the outdoors. Cut-throughs between rooms can also help each room seem larger.
Furniture can be grouped differently in a smaller room to make it seem larger. Instead of centering a large table and building around it, homeowners can break off the room into separate gathering spaces. Chairs can be grouped around smaller coffee tables in the corners, and individual area rugs can define the spaces. Wall to wall carpeting can make a small room seem even smaller, especially if the traffic area around elements seems crowded.
One final room expansion trick involves paint. Skilled artists can create three dimensional murals which fool the viewer into seeing more depth in the room. One wall could be dedicated to an outdoor scene done in a natural perspective. On a smaller scale, lighter shades of paint tend to create a greater sense of airiness and space. Combine a lighter color scheme with smaller pieces of furniture to complete the illusion of more space.