Really really listen, and steer the conversation with questions. Focus on real pain they have that your product can solve. Let them come to realize for themselves that your product will solve real problems for them, and then get the hell out of the way while your partner closes.

You're selling something you believe in. That makes it easy.

A specific book I'd recommend is "SPIN Selling" by Neil Rackham. He did actual research into successful solution sales cycles. He outlines the best way to go about making somebody realize that your product is exactly what they want. It's from 1988, but most tactical solutions-selling books since have felt to me like a branded rehash of SPIN Selling.