John Maeda's Rules of Simplicity

1. A complex system of many functions can be simplified by carefully grouping related functions.

2. The positive emotional response derived from a simplicity experience has less to do with utility, and more to do with saving time.

3. When the richness of an experience is increased in a manner that facilitates the perception of the overall intent, by all means don’t skimp. Add more!

4. The more you know about something beforehand, the simpler it will ultimately be perceived.

5. A material’s failure to comply to a specific application provides indication that its more natural usage lies elsewhere.

6. In order to “feel,” you gotta have noise. Too much noise, and all you’ve got is noise.

7. The more care, attention, and effort applied to that which is less, the more it shall be perceived as more than it really is.

8. Recognize not only the absolute laws of the physical universe as important constraints, but also the artificial laws as of equal importance when striving for simplicity.

9. Simplification most commonly occurs through conscious reduction; the more uncommon form involves subconscious compression.

10. Less breeds less; more breeds more. Equilibrium is found at many points between less and more, but never nearest the extrema.

11. Simplicity is about subtracting the obvious, while adding the meaningful.

http://weblogs.media.mit.edu/SIMPLICITY/