TReil & Error Design Principles

1.      A product’s design cannot be defined as simple until the user perceives it so. 

2.      Allowing user complaints and recommendations to drive new requirements will only lead to minor improvement, not true innovation

3.      Forget the debate. Form and Function should be seamlessly integrated. 

4.      A product's perceived primary function and overall purpose is put at risk as the complexity of the product's architecture is increased.

5.      The design and development of a product will always extend longer and contain more errors than expected. Plan accordingly.

6.      Prediction of the future is impossible. It is necessary to plan for a range of potential adjustments that align to plausible future states.

7.      People are self-interested by nature. Don't show them how great your product is, but instead show them how great they'll be with your product.

8.      Once people progress beyond basic needs, they seek out meaning in the products they purchase. Showcase the purpose within a design.

9.      Where there is redundant form or function across a product line, there is opportunity for modularity in the architecture.

10.  People inherently reduce pain, discomfort, or uncertainty. Create natural and intuitive user interfaces if you want people to use your product. 

11.  Technologies are almost always combinations of, improvements upon, or re-applications of other technologies. They are rarely invented.

12.  The product’s life extends beyond its original use. Design for recycle, alternative use, or decomposition.
13. Prototype, prototype, prototype... you can't truly understand your ideas without making them tangible first.
14. Good design is useful (credit to Dieter Rams for this one).