A mix of pillows covered in colorful plant imagery

Arranged on an all-purpose Ikea Stockholm sofa, this collage of pillows is a concept-driven blend of texture, scale and shape. The mix is kept from spinning out of control and into a random hodgepodge by (1) the unifying theme of plant imagery conveyed in strong colors, and (2) the repetition of figurative patterns set against solid neutral backgrounds.
Aqua blue pillows

A symmetrical arrangement is inherently easy on the eyes because the brain processes patterns more quickly than it does erratic layouts. Rather than have pillows of all one size, which would be monotonous, the narrow lumbar pillow at the center draws the eye in from the grouping's outer edges. In terms of color, the bright, aquatic blues vibrate in their close contrasts to one another, while the white trim work makes constant reference to the sofa's upholstery.
Red pillows with handcrafted textures

A cascade of pillows, roughly ordered from large to small, left to right, replaces the couch's back cushions and transforms it into a daybed, irresistible to anyone inclined to recline. No two pillows are alike here, but the handcrafted textures and red theme pull them all together. An embroidered throw stretched across the seat gives the impression of a full-length cushion.
Black-and-white pillows

A palette of black and white is a deceptively simple concept—the two-tone scheme feels clean, modern and anything but drab, thanks to contrasting patterns. And grouping items in odd numbers is a classic design trick: They make a stronger impression because the eye instinctively reads each component, whereas in even-numbered groupings the eye automatically sorts the components into pairs.
John Robshaw, designer

Three designers go behind the seams to share their pillow principles. Their strong (and sometimes conflicting) ideas reveal that, as always, an object's beauty depends on its beholder.

John Robshaw says, "I like opulence and more! more! more! Some people use only two pillows on a giant sofa, which I think is too fussy and precious, but I'll put them in a big pile on the floor—it's much more sculptural that way. Try odd-shaped and big pillows. And if you can't find what you're looking for, then make your own or ask your dry cleaner to make you one with your favorite fabric. Have more pillows than you need so that it's not as if you're trying to draw with only three colors. Overbuy and mess around."
Sheila Bridges, designer

Unlike John, designer Sheila Bridges takes the "less is more" approach with her pillow preference. "I design pillows I'd want to live with in my own home. I prefer square pillows for their symmetry, and I like a crisp, tailored look, which is why I don't use a lot of fringe or tassels. I don't mind a little embellishment, but I don't want anything that would make the pillow uncomfortable.

Breathable, natural materials like linen and cotton are my favorites. They're easier to clean than silk and feel good against the skin. I love florals and stripes, too. You can mix the designs if you have a color that ties the pillows together.

I don't care for a ton of pillows on the couch. If you're collecting, that's one thing, but too much of even a nice thing makes an object lose its uniqueness. Pairs create balance, and a single in the middle of a love seat will make the pillow seem special."
Michele Varian, designer

If you're still confused about which pillows will complement your home, designer Michele Varian offers a few shopping dos and don'ts:

Lose the swatch.
"A lot of times, people bring their sofa swatches in to make exact matches between pillows and their sofa. But I don't think the eye is so sophisticated that an exact match is necessary."

Shop early.
"Another mistake people make when they buy pillows is that they wait until they're nearly finished designing a room, when they don't have a lot of juice left—financially or mentally. Start looking at pillows early, even if you can't purchase them for a while. Even more than architecture, textiles and color can transform a space. They're what we respond to first."

Buy what you love.
"What I'd like to achieve with my pillows is the antithesis of people walking around with swatches: I'd like people to purchase pillows because they love them, much in the same way a person buys a handbag or a piece of clothing because she can't live without it."