dieter rams: 10 principles for good design

Good design is innovative.

Good design makes a product useful.

Good design is aesthetic.

Good design helps us to understand a product.

Good design is unobtrusive.

Good design is honest.

Good design is durable.

Good design is consequent to the last detail.

Good design is concerned with the environment.

Good design is as little design as possible.

(references: 1 2 3)