Backstory: The prospect runs a fairly established internet business and sends out ~10 million notifications a month, and they were in the process of building an in-house notifications system. They had come across us randomly at a conference. They felt they would save a lot of time if they went with us, and could re-focus their engineering efforts on their core product. However, they were worried about using a fledging product and also needed a few extra features in order for our product to be useful to them.
We couldn't help the fact that we were a new product in the market. So, we focused on the things we could control -- We worked hard and built those extra features as fast as possible in order to prove ourselves. Once we were done, we asked for a follow-up meeting, but never heard back. We were flush with doubt - Was our product not good enough? Was there something wrong with our offer?
Fast-forward: Two whole months went by, and all of a sudden, we were asked to demo our product in-person. :) With renewed confidence, we went in, demoed our product, and got a verbal confirmation from the customer that we would do business together. (Woohoo!)
Lesson learned: Be patient. Sales cycles with bigger customers take time. Listen to your customer's problems and solve them.