When the ball is rolling, you must be responsive. Return calls and emails promptly, even if you don't have all of the answers. Once the relationship has traction, it is your responsibility to keep the momentum. Do not try to close too soon. Think of it as a ratcheted process.
Every step is important.
Visualize the outcome, believe in yourself and the process, and move it forward one step at a time. Don't be scared. When you've decided to proceed, do some of your own due diligence. Make some calls and ask around. Find out if this is someone with whom you want to deal.