Clients often ask me how to impress a Venture Capitalist (aka "VC"). I tell them to make their presentation short - no more than 10 PowerPoint slides. Practice, practice, practice telling their story. Do not read it. Start with something grabby: an unusual, powerful fact about the need in the market or a question that will get the VC thinking about some problem or pain in his/her own life that their product or service solves.
Recently, I've started following an online columnist for Forbes, Peter Cohan, who often writes about the same topic - getting a VC to listen and take interest in investing in your company. Cohan makes good points and shares excellent insights from successful entrepreneurs and investors. You can tap his wisdom at his blog Forbes: The Startup Economy by Peter Cohan.