Accessorizing your home is a lot like accessorizing your wardrobe. The same way that a pearl necklace complements a basic black dress and a fine silk tie adds color to a man's suit, pillows, throws and finishing details can enhance the look of your living room couch. In most American homes, if there is no fireplace or other architectural element, the couch is the focal point of the living room. When you "dress" the couch, your entire room is enhanced and personalized. Think of your couch as that basic black dress or plain suit. Then think about using pillows, trims and blanket throws to express yourself and define your decorating style. Choose carefully what you put on your couch ... and what you leave off!
First, get rid of the little throw pillows that "come with" the couch. Unless you have pillows custom made by the furniture workroom (and pay for it), the pillows that arrive with your couch are generally not worth keeping. They are often too small, too plain and are filled with cheap, lightweight synthetic stuffing. They are the Pringle potato chips of home decorating: a poor imitation of a great original. Keep the Pringles off the couch. While you're at it, lose those "arm protectors." There is only one good purpose for these. If it is raining the day they deliver your couch and you need to run out to the truck to tip the driver, put one of these on your head to keep your hair dry. Then throw them out.
You shouldn't let decorating intimidate you because it's mostly common sense, and it ought to be fun. If you can match your belt to your shoes, or choose a nice necklace and a pair of earrings, you can handle the living room. You'll see that many principles of wardrobe accessorizing can be applied to interiors. In both clothing and interiors, it's all about scale, pattern and color.
Scale is simple: If your sofa has cabriole legs, a graceful camel back and a trim, cushionless seat, don't overwhelm it with massive, overstuffed pillows. (You wouldn't wear big wooden clogs with a slip dress, would you?) Likewise, a tiny, delicate pillow would get lost in your extra plump chair-and-a-half. (Picture a baby tee shirt with a full length taffeta skirt!) Scale applies to pattern as well. If you want to mix patterns, the trick is to vary the scale. A couch that is upholstered in a large scale floral fabric looks well with pillows in a smaller plaid or check.
As for color, aim for harmony, not an exact match. Rooms in which everything matches are boring! I can't tell you the time wasted by well-intentioned home owners who carry clippings of carpet fibers and snippets of fabric to decorating galleries and labor over matching everything exactly. What they get for their effort is an uninspired, predictable room. A jean jacket over a chambray shirt with blue jeans and a denim backpack would be terribly dull. So would dressing in all one color. Here's a hint: choose a minor color from your couch fabric and feature that color in your pillows and accessories. It will make your color scheme pop. Be the Carrie Bradshaw of decorating. Use an unexpected color or texture that doesn't "match" anything else and see what a difference it makes.
Blanket throws do for a room what a colorful scarf does for an outfit. In addition to providing warmth on a chilly night, they add that bit of color, texture and sophistication that completes a look. I reserve my throws for the cold weather months. I launder or dry clean them every spring and pack them away in the linen closet when the weather turns warm. After not seeing them all summer, they are a welcome sight when I finally bring them out again. There is an endless variety to be had, and prices to suit everyone. Some people have trouble achieving that casual "thrown" look. Here's how: flip down a cushion on one end of the couch. Drape the throw over the corner of the couch back and flip the cushion back up. Done.
Whether you buy your cushions at discount stores, or have them custom made, the filling you choose will go a long way toward creating a look of quality. Feather and down inserts are my personal favorite. An inexpensive pillow can be enhanced by replacing inferior stuffing with a good quality insert. Marmelstien's in Philadelphia has inserts in lots of sizes and shapes, and if you are an Internet shopper, you will find an infinite variety on line.
If you have your curtains made, order some extra fabric and have it machine-quilted and made into pillows. The quilting adds depth and interest. I once collected old plaid stadium blankets, cut them up, and made pillows for a client's lake house. The plaids were all different, but the colors were harmonious, and I used the long fringe on the blankets to trim the edges of each pillow. The effect of all the pillows together on the couch was beautiful and very unique.
Consider adding tassels or trim to a plain pillow to add style, and look for old needlepoint seat cushions at tag sales for an English "heirloom" look. These can be made into one of a kind treasures by a seamstress or decorator's workroom. Avoid deep, full ruffles. Deep ruffles on pillows are the equivalent of "big hair." Very 1980s. Opt instead for a loosely gathered, narrow ruffle or a contrasting grosgrain ribbon inserted into the seam. You can never go wrong with narrow cording covered in the same fabric as the pillow.
A final word: Be careful not to overdo it with accessorizing. My sister's husband swears that people with lots of "stuff" on their couches don't really want you to sit down. While I wouldn't go that far, I see his point. It can be awkward for your guests to perch on the very edge of the couch because your pillows occupy the best seats in the house. And no guest wants to see you strip the couch of all its finery just so they can sit down. One or two well-chosen pillows and a small blanket throw are better (and cheaper) than an army of stuffed beauties lined up across your couch. Too many pillows are like too much jewelry: you don't want to look like you're wearing everything you own, all at once.