AThe first thing you should do is go through your possessions and cull anything that you don't like, use, or need. As William Morris, the 19th century English designer/writer once said, "Have nothing in your house that you do not know to be useful, or believe to be beautiful."

Once you've removed what you don't need, you will be able to make better use of your new-found space. Survey each room in your house inch by inch and, thinking like a ship designer, try to imagine ways to convert neglected areas into useable space.

First look up. If your ceilings are high enough, consider building a continuous shelf around the perimeter of a room, 12-18 inches from the ceiling. In the kitchen, this shelf could hold glasses, vases, or bowls. In the living room you could put books or collectables up there. In a child's bedroom, this could be a place for toys or dolls that are not used any more but also can't be given away yet.

Now look down. Explore opportunities to use excess space to add built-in cabinets or shelving. Underused space like the area under a stair could be used for bookcases or even a small powder room. In kids' bedrooms, you could build loft beds above desks or drawers below beds. Do you have an area for a seat and a reading lamp in a stair hall? How about a window well in the kitchen where you can grow herbs?

One way to increase the perception of space without enlarging a room is to add windows. By doing this, you are visually extending your space outward. Try to keep the sill height no more than two and a half feet above the floor so that the outdoors looks like a continuation of the room. Two windows placed together in a corner also can create the effect of extending room limits.

Sarah Susanka, an architect who wrote several books on the virtues of not-so-big houses, noted the expansive properties of diagonal sightlines, "If you can stand at one corner of the house and look to the far corner, you will think your house is much bigger than it actually is" - a view she attributes to the geometric concept of the hypotenuse of a triangle being longer than either of the two sides.

Susanka also suggested adding an architectural element in the middle of a room. This may seem counterintuitive, but she says that if you add a wall, pillar, or low bookcase, you actually slow down the eye and are creating a room that feels larger because the space is better defined.

Making effective use of the space you have is good sense architecturally, perceptually and financially. By appointing areas of your house to be useful and beautiful while defining space boundaries, you will be able to create a house layout that works more efficiently and feels more spacious.