One of the keys to the process of designing is modeling the idea. This can take a variety of shapes, but the idea is find a way to stimulate and test the idea. This will result in many discoveries (failures) before the final solution is identified.
Article: Rapid Prototyping: The Wright Way to Fail
Also check out Method's series on innovation, 10x10, from which this article is taken.
Method's "Innovation: Wrapped, Packed and Stacked"
Howest University College, (5-day hands-on prototyping course)