Guiding design principles from Google... 1. Focus on people—their lives, their work, their dreams.
2. Every millisecond counts.
3. Simplicity is powerful.
4. Engage beginners and attract experts.
5. Dare to innovate.
6. Design for the world.
7. Plan for today's and tomorrow's business.
8. Delight the eye without distracting the mind.
9. Be worthy of people's trust.
10. Add a human touch.
It's very hard to do all of these well, but it's certainly worth understanding the important things to strive for. Too often companies (including mine) get too caught up in the technology and either forget about simple utility or have a very, very complicated definition of utility that winds up violating most of the above principles.