I know people who find this aspect of writing to be the most challenging—after all, a writer should have to write, right? Publishers should come to us! But, they don't, I'm sorry to say. In fact, once you choose that perfect publisher, you have to essentially sell it to them. Even a brilliant story won't get out of the slush pile if you don't write a brilliant query to go along with it. However, that is a topic for another day. In order to get to that slush pile, you would have already chosen that publisher as the one you absolutely want to publish your book.
Of course, that might not necessarily be true. I know some people who aren't as picky—they send to any and every publisher willing to look at it. That strategy has its advantages and its disadvantages. On one hand, your work is seen by more publishers. They may not like it—they may even think you're a negligent author for not reading their guidelines and submitting something completely different from what they want to see—but the point is that they read it, right?
Personally, I don't like to do that. To me, it feels a little like whoring myself around. The highest bidder gets what I'm offering. But that's not to say that the technique doesn't work. I'm sure at least one of those publishers will take a peek.
For those of you who feel like I do, and want your baby to go to the most loving home you can find, I'll continue writing the way I narrow down the publisher. It all comes down to 5 things:
1) I read the guidelines. This, I think, is the most important one. It lets you know if the publisher publishes in your genre, what they're looking for in a story, and the proper way to send it in. If you get all your ducks in order, you're much more likely to get that manuscript into print.
2) I read through what they've published before. No, I don't read all of it—that would be ridiculous. After all, unless this is a publisher I currently read a lot of, there would be a lot of stories to go through. In fact, one effective way to do it (for those of you groaning about reading through everything) is to stick to the blurb that you would see on the book's webpage or on the back of the book. Generally, it gives you a flavour as to what the book will be about, and therefore, it gives you a taste of what this publisher publishes. The more you read, the better informed you will be.
3) I ususally skim through the list of author names. I am fairly wide-read in my genre, and therefore if I can pick out one or two authors I know, the publisher passes inspection. In general, if you read what you write (and it is always helpful to do so), finding a name you know on the list will in itself let you know if the publisher publishes stories in the same vein (no pun intended) as yours.
4) I browse through the website. Publishers work hard on their websites, because it is the window into their trade. It is, essentially, the way to attract writers to submit to them. There is usually a distinct tone to a website, and through browsing it thoroughly, you can become acquainted with the sort of feeling they want to embody in their books.
5) Lastly, I take a look at the editors' blogs. While these may or may not pertain to writing, what it does let you know is the editors' personalities. I always find it much easier to submit something once I feel that I know the person on the other end, if only through a webpage.
Yes, I realize what I've suggested details a lot of work. But that's what writing is—work. If you want to make money, you have to put in the time. Otherwise, you might as well let that prized manuscript of yours rot in a drawer. Since you probably don't want to do that, I advise you to learn as much as you can about your chosen publisher before you submit. It will help you out in the long run.