First of all, the incorporation of natural woods. Wood tones always soften the tone of a room by infusing it with a touch of rustic.
Next, restraint. It's easy to go over board with black and white and end up with a dizzingly dramatic space. However, if you want to achieve a subtler look while still preserving an air of crispness, try reserving the black for limited for trims, doors, frames, or key pieces of furniture. My favorite example is the black paint below the chair rail in the first picture. A totally black hallway, or even black paint above the chair rail, may produce a tunnel vision effect. However, leaving the top section an airy white and tying the black bottom half in with the black chandelier, creates a calm but elegant entryway.
Finally, a variety of textures and finishes. For either black or white, using high gloss paints for some pieces of furniture while painting others in a matte finish creates a pleasing visual contrast with just the right amount of un-uniformity.
(Images: 1: Skona Hem, 2: via delight by design, 3: Elle Decor of Darryl Carter's Virginia Farmhouse, 4: Country Living, 5: Elle Decoration, 6: Belle Magazine via Emmas Blogg, 7: William Waldron of Nate Berkus's NY office)