One of my colleagues recommended to read the book "Pitch Anything: An Innovative Method for Presenting, Persuading, and Winning the Deal".
I just started going through and I loved it! You will understand, why!
From one of the reviews: "Read this book if you're frustrated with your current sales method, if you're tired of making 100s of calls for making 2 deals, if you feel angry with the way you're treated in client office lobbies or if you just want to try something different."
http://pitchanything.com/