User-centered design means working with your users all throughout the project.

Good design is also an act of communication between the designer and the user, except that all the communication has to come about by the appearance of the device itself. The device must explain itself.

We delude ourselves if we believe that skilled behavior is easy, that it can come about without effort. We forget the years of tuning, of learning and practice it takes to be skilled at even the most fundamental of human activities: eating, walking, talking, reading, and writing. It is tempting to want instant gratification - immediate expert performance and experiential pleasure - but the truth is that this primarily occurs only after considerable amounts of accretion and tuning.

Simplicity design axiom: The complexity of the information appliance is that of the task, not the tool. The technology is invisible.

The argument is not between adding features and simplicity, between adding capability and usability. The real issue is about design: designing things that have the power required for the job while maintaining understandabili ty, the feeling of control, and the pleasure of accomplishment.

A challenge to the designers of the world: Make signs unnecessary.

In my opinion, no single design is apt to be optimal for everyone.