Google’s some creative people shared techniques and systamatic approch to the google’s design. They have uploaded “Visual Design Guidelines” two series to

According to the guidelines, Google likes its product icons to be “highly simplified, exaggerated and caricatured in nature so that they are appropriate for use at small sizes.” The company’s new icons are also geometric shapes that are front-facing, with straight, hard shadows.

Check out the part1 and part2

Google Visual Assets Guidelines