to publish a work of narrative non-fiction. I've had dozens of bites and a few crushing disappointments and am about to try again. It's a long process that requires a lot of research, patience, and persistence. Lots of people will tell you exactly how to go about it, and yes, there are a few general rules, but I've learned they're not as hard and fast as some people would have you believe. Here's the procedure, based on my experience:
1. Finish (read: perfect) your manuscript, preferably with help from other experienced writers and at least one ruthless editor.
2. Research the agents and/or publishers you want to approach. I've had luck with both. You can use the internet, but it's helpful to invest in a guide to literary agents and publishers.
3. Write a really good query letter - 500 words for email submissions, one page for hard copy. Put as much thought and effort into it as you did your first chapter.
4. Follow each agent's or publisher's submission guidelines.
5. Send out a few at a time. Don't send mass queries. The shotgun approach is not effective - you might get some hits, but might also shoot yourself in the foot with some prospects.
6. Be prepared to send whatever they ask for - sample chapters, an outline, a synopsis, a full proposal, or any combination thereof - fiction or non-fiction, it doesn't matter. Once you create something, save it and expect to have to change it to suit another agent or editor.
7. Be prepared to spend a lot of money on postage, and don't forget the S.A.S.E.!
8. Keep track of what you send to whom.
9. Wait anywhere from a few days to a few months for your replies.
10. Seriously consider any feedback you get, and don't be offended.
If you're serious, there's plenty of information on the net to get you started. Here are a couple of sources I like:
http://www.writersmarket.com (worth the subscription, in my opinion)
http://www.writers.net (good discussion forums)