I've also tried whitepapers or ebooks with limited success. On the phone, people often assume they are marketing pamphelets and hold no value.

I have had success with inviting people to educational lunches with catchy titles. Name dropping competitors you are speaking with is something you can try to pitch attendance. The effectiveness of that varies by market. I think educational marketing works...you just need to find the right vehicle. I highly recommend Chet Holmes's 'Ultimate Sales Machine.'

Depending on your price point and geography I think simply setting up a meeting is a great first step. Most businesses are secretly relationship businesses. Taking an interest in a set of ideal customers and really building a relationship pays dividends in my experience.

edit: Thanks for the kind words. I am happy to chat about it. I hope more people take something away from it. Forgive me for losing focus and not putting the thank you in the original comment.