You may want to read this article, where Ryan Sarver (previous platform guru @Twitter and other) describes his transition from being a startupper to a VC, and what difference it makes in the perspective of risk, time, success factors.
The reason this is important if you are on the startup front is because you have to think in this terms to optimize your value story, and determine what are the most relevant components of your idea; how a balanced, well thought approach provides a better assessment of a business idea. Put your innate optimism away, look at your plan critically, attack it from various angles.
And if it stands all your critics and doubts, be proud, just make the best presentation ever!
