Choosing the right carpet for your home comes down to three basic check points: Color, Texture, and Size.
Color
Color is the obvious starting point here. If you already have a lot of color and pattern going on in your space, you might want to stick with a single-color rug, either a neutral or a shade that complements your existing furnishings. If you want a patterned rug with many shades, it's generally easier to choose it first, then add furniture and accessories that coordinate afterwards.
A rug will read as one of the largest pieces of “furniture” in the space, so be sure to take into account the tones in your flooring, walls, and other fixed finishes when selecting. But don’t play it too safe — a boldly patterned or brightly colored rug can elevate a room to the next level.
Texture
Texture is one of the most overlooked elements when choosing a rug, but it's incredibly important. A room with a mix of different textures feels rich and layered, and a rug is one of the easiest ways to set that tone. There's much more available than just cut and looped wool!
Let the finishes of your existing furniture guide you and aim for contrast. With seating in a soft fabric like velvet, something smooth and hard like sisal may be ideal. Conversely, a sleek leather sofa looks great on a longer, fluffier pile.
Keep in mind the practicalities of cleaning the rug, and consider whether elderly people or those with limited mobility will be using the area — raised or shaggy piles can be tripping hazards.
Size
Size is usually the part people know the rules for — and it's generally best to follow them. A rug should fit the size of your seating area (not always the entire room) and be as large as reasonably possible within that area.
Ideally, all furniture pieces should sit fully on the rug, but having only the front legs on is a common and acceptable compromise. The goal is simple: when sitting on the sofa, your feet should be on fabric, not on bare floor.
Under a dining table, the rug should allow chairs to be pulled back while remaining on the rug. When the seating area occupies the whole room, consider orientation: square rooms suit square or round rugs; rectangular rooms look best with rugs aligned in the same direction.