One of the designers of Google Apps, Jon Wiley, tell us some guideslines that usually follow to design in Google, and that presents in the conference ” Writers UA”. Wiley

1. Useful: focus on people – their lives, their work, their dreams.
2. Fast: every millisecond counts.
3. Simple: simplicity is powerful.
4. Engaging: engage beginners and attract experts.
5. Innovative: dare to be innovative.
6. Universal: design for the world.
7. Profitable: plan for today’s and tomorrow’s business.
8. Beautiful: delight the eye without distracting the mind.
9. Trustworthy: be worthy of people’s trust.
10. Personable: add a human touch.

Source: Googlesystem