Our perception is relative. That is, we often perceive things in how they contrast or differ from other things. Sometimes we perceive them as similar or the same. Human perception tends to compare and contrast, thus if we are mindful of the mechanisms of perception, design could be used to steer or influence (but not control) perceptions.

Create contrasts in materials, sizes of adjacent spaces, proportions of details, to make those details stand out.

In particular, use contrast in places where you need to get attention - such as directing people's attention to the entry of a building.

Examples of contrasts include: round vs square, tall vs short, dark vsslight, hard vs soft, smooth vs rough, cocave vs convex, many vs few, simple vs complex.