Be professional.
The more professional you look the more willing the editor will be to give you his much-sought-after time. In the case of my publishing house, Kunati, we accept submissions from unpublished, unrepresented authors and we accept them by email. This is almost unheard of in the industry. It gives writers unprecedented access to a publisher. But it does not give writers the right to toss off a poorly written, badly spelled, incomplete query that shows a total lack of respect for the person reading it. Me.
Instead, compose your query carefully with emphasis on the book, not on yourself. State simply and clearly what it is about, what it is called, how long it is, why you think it should be published and why you think it should be published by the particular publisher you have queried. On this latter point you need to have done a little research so that you do not send lace to a gingham buyer. As obvious as it may seem, be sure that you send your query about an illustrated book of garden flowers to a publisher who publishes that type of book. Failing to follow this simple rule will guarantee a rejection. And who needs rejection?
Be sure that your query and other materisls have been checked for spelling, grammar and punctuation. You are a writer. Demonstrate as much in everything you write. Do you think an editor will be impressed by a query full of errors? Or do you think the editor will say to himself, if I take on this "writer," I will be making more work for myself, correcting all his errors?

Follow submission guidelines
Every publisher and literary agency has its own guidelines. Read them before you send anything. Don't send a complete manuscript if the guidelines stipulate three chapters. Don't send hard copy if the publisher (Kunati) prefers electronic. If the submission guidelines request a synopsis, include one. And here's a little secret: nobody likes to read a synopsis. They are almost invariably boring and badly written, but they're necessary, sort of. Speaking entirely personally here, I hardly read them. I skim to look for main plot points, main characters, a sense of beginning, middle and end. And this is important: include the ending of your novel in the synopsis. Don't be coy and think that you're going to tease the editor into asking for your manuscript. Tell me how your story ends so I'll know that you know how to tell a story with a reasonable, logical conclusion. And keep it short. If you send me a ten-page synopsis I guarantee you will put me in a bad mood. Is this what you want from your potential best friend?

Be careful when you "follow up"
This point pertains particularly to my work at Kunati, but I'm sure there are equivalents in other author-editor relationships. Because we accept email submissions, we get a lot. Really. A lot. I keep them in folders with labels such as November Queries, Active Consideration, Non-Fiction and so on. If you have queried Kunati and wish to do a follow-up because you haven't heard from us in "six months," be sure to send your follow-up from the same address as your original query came from, and be sure to include the exact date of the original query. This is important because when an author emails me a follow-up, it makes me feel guilty. When I feel guilty, I must make the guilt go away by whatever means. So I will search for that original query until I find it, and then respond. If I cannot find the original query, I will feel even more guilty, thinking that I might have deleted it, or somehow lost it. At this point I will respond to the author doing the follow-up and apologize for not being able to find the original query. If the follow-up author then replies— "Oh, did I say March? I meant July. And by the way, I've got a different email address now. Could that have something to do with it?"—which emotion do you think will replace the aforementioned guilt?

I'll have more to say about how to become a published author with a happy editor in coming days.

James McKinnon is editor in chief at Kunati