This article was published in the California Management Review from the University of California, Berkeley back in 2007. However the way it is structured is still topical and relevant to the innovation practices around the world. 

The innovation process returns to the concrete realm to generate solutions, choose the ones that best meet the imperatives, and test them with potential customers or users. This part of the innovation cycle is, perhaps, the best documented and exercised in practice. 

Based on the imperatives, which firmly connect back to the observational research, the innovation team can use a wide range of concept generation techniques to come up with alternative solutions, a well-documented set of concept selection techniques to choose the solutions they wish to take forward, and then a variety of mechanisms for soliciting feedback from potential users.