Thanks to a link from Cynthia Leitich Smith, I’ve just discovered the website of Cheryl Klein, an editor for Arthur A. Levine books at Scholastic. She’s got some great content on there, and I really like her article on plot (especially the ideas of first and second drafts focusing on different things), and especially the article on how finding a publisher is like dating and falling in love. In mentoring me, my senior editor has also used that comparison–submissions are like wooing, you don’t want to give too much away too soon, and sometimes you have to “break up” with an editor or an agent.
In that article, she’s got great advice for writers as the “pursuer” and publishers as the “pursued.” For example (I’ve made her points into paragraphs because I don’t know how to do bulleted lists in HTML and it was going all wonky):

So it’s your job to introduce yourself and your book in a way that will be attractiv
e to the pursued. In the dating world, this is known as a pick-up line. In publishing, it’s called the query letter.
What sets a yes apart from a no, in dating and in publishing?
Personality—Something interesting to say, that we haven’t heard five hundred times before;
Expression—said well. Basically, it should sound like jacket or catalog copy for your book.
Interest in the other person—that emphasizes why the listener (the editor) is right for the speaker (the book).
And—it has to be said—a nice, clean outward appearance, with no copyediting errors and a self-addressed stamped envelope.
Do NOT emphasize numbers like word count. Equivalent of taking your date out and reciting your ACT and IQ scores. Interesting, but only relevant if the rest of it works out.
It’s often helpful if you can compare your book to another book the editor might know—especially one of the editor’s books. It allows us to get a handle on it, and it shows you’ve done your research….
Now, queries don’t have to be exclusive—you can send out more than one at a time. But you should try to tailor each one to the editor to whom you’re sending it. Nothing more off-putting than when I get a query letter addressed to Samantha McFerrin at Harcourt—which happens sometimes: It’s sloppy on the writer’s part, and it’s not personal to me. Do note it’s a simultaneous query, though.
Just like in relationships, you need to be honest with everyone involved.

If you’re a new writer looking for advice on submitting, it’s great advice. She’s also got some suggested reading lists and advice for young editors.
Which reminds me that I’ve been meaning to post my own recommended reading list. Maybe I’ll try to do that over vacation. I’m off tomorrow to visit the family and go to a drum corps reunion. Happy 4th of July!