For a design to be memorable, it must have depth. How is depth achieved? Variety.
Regardless of style or aesthetic, shape, layout, location or purpose of a space, every piece within it brings its own unique character to the design. How everything goes together is a different story, but, a surefire way for enhancing visual interest is by taking inventory of a few simple elements: colors, patterns, textures and materials (natural & synthetic).
Think in terms of each category individually and then as a whole. The more variety you integrate into each, the more you end up with as a whole. Variety influences the level of energy and stimulation felt in a space - more is more, less is less, and none is flat and boring.
That being said, different aesthetics place emphasis on certain elements over others. For example, materials and textures play a central role in both rustic and industrial designs. With rustic, you tend to see tons of natural woods, leathers, wool and fur. Earth tones are often the color palette, however color (and patterns) are typically more muted and intended to take a back seat to natural materials.
Similarly, industrial designs are often comprised of concrete, chrome, stainless steel and exposed brick. Colors are often very subdued, made up of mostly black, white and shades of grey, complimenting the stark/clean lines of the furnishings.
On the other hand, bohemian and island styles heavily utilize color. Bright, vibrant pink, orange, teal, yellow, etc., can be found in most bohemian designs, whereas pastel blues, yellows, greens and coral are typical for island/beachy looks.
Monochromatic designs center around one or a (small) handful of colors, but require textures to bring the spice. For example, an all white bedroom can be enhanced by diversifying the fabrics used for bedding, incorporating a textured woven area rug, subtly patterned lamp shades, velvets, ruffles, etc. Just because you’re working within a very defined color palette, doesn’t mean you can’t layer extensively.
Color
In these examples, color plays a dominant role, however if you look closely you can still find patterns, natural and synthetic materials and textures blended in.
Textures & Materials
These three spaces showcase emphasis placed on texture and materials. Colors and patterns are less of a focal point.
Patterns
Patterns can be integrated in many different ways - flooring, wallpaper, blankets, art, rugs, upholstery, backsplashes, lighting, etc. They can be played up or down depending on how busy they are, and add dynamic contrast even when they’re more muted.