As the former CTO of Stanford University, Raman Khanna of Onset Ventures spent more than a decade sifting through proposals from faculty members who hoped to commercialize their research.

It was a perfect training ground for being a venture capitalist, says Khanna, who invested in many Stanford entrepreneurs after he left the university to found Diamondhead Ventures.

At Diamondhead, which merged with Onset last year, Khanna worked with an ecosystem of faculty advisers and industry executives to help sift through the ideas.

The most frequent fatal flaw?

"About 90 percent of the ideas were too early," says Khanna, who in earlier Vator.tv interviews talked about investing in hardware, the online ad market, early-stage valuations and lessons he's learned as a VC.

"These professors were often thinking five-to-ten years down the road," or long before the market their product was targeted at would arrive. 

Another problem were "professors who were used to being in charge," or who were perfectionists, and refused to either cede control of their company to a CEO with business experience or would delay the release of a product rather than launching it and letting customers provide early feedback.