Consider what shape of area rug you want for your living room. Select a rug that complements the shape of the furniture and other rugs in the living room. Choose a rug that has the same shape as the furniture you place it under, or give the living room variety. You can also play with contrasting shapes. Buy an area rug that has a different shape than the other rugs. A rectangular area rug in the center of the living room would offset circular furniture and smaller rugs and vice-versa. Remember that opposites attract.
Choose an area rug based on its size. Consider the placement of the area rug in the living room. Buy a moderate size rug if you intend to place the rug underneath a table or chair. Purchase a larger area rug if you plan to place it on an open space such as in front of the fireplace. Avoid buying an oversized area rug that overlaps other rugs. Avoid placing the corner of the rug in the center of an entrance into another room to prevent tripping.
Choose an area rug with a pattern that is complementary to the surrounding living room furniture and wall accessories. The pattern and color scheme of the rug should pick up the colors of the curtains or blinds. Choose a solid area rug color if you have a variety of colors in your living room. A solid color will create balance.
Choose an area rug that highlights the existing floor. Select a smaller area rug if you want to highlight the floor. Find a larger area rug if you want to downplay the floor. It is probably best to pick a multi-toned rug for a floor that features a consistent pattern, and a solid-color rug for a patterned floor.