Being a good designer isn't just about putting the right stuff together: it's about the way you see the world. A really important concept in design, and one that's perhaps hard to explain without concrete examples, is the idea of balance. The objects in a composition (in this case, a room) are always in tension with one another. It's the contrast between opposites — black and white, smooth and textured, heavy and light — that makes things interesting and, ultimately, beautiful.
Smooth vs. Textured
In both of the rooms above, it's the tension between the smooth white walls and the more complicated, textured elements that makes things interesting. In most rooms, a big expanse of uncovered white wall would read as boring, but here the more textured elements (like the table and chairs and the rug in the dining room up top) balance out the walls and create a pleasing composition.
Heavy vs. Light
Filling a room with a bunch of big, solid furniture pieces can create an oppressive, stuffy feeling. Here, the wire chair and the lucite table help to balance out the heaviness of the couch.
Colors vs. Neutrals
Maxwell's 80/20 rule comes into play here: it's the idea that each room should have about 20% 'high color' balanced out with 80% neutral color. Of course a neutral color doesn't have to be grey. It could be pink. But the idea is that it's important to maintain the balance between bright, showy colors and more soothing background ones.
Old vs. New
I love the look of antiques and modern pieces mixed together — the marriage of the two creates a kind of beautiful tension.
Warm vs. Cool
You don't always see warm and cool colors in the same room — if you look closely, you'll notice that a lot of rooms have only either cool shades or warm shades. But the two together, in the same room, can be very nice... just be sure to follow the 80/20 rule (or something like it) and keep one color as the accent and the other as the 'main'.