Editors and agents deserve your respect, your courtesy, just as any other human being does. But these people — as well as any other people in the publishing business, from typesetters to art directors to the postal employee who delivers your acceptances and rejections — have no reserved spot on any publishing pedestal. The only pedestal you should recognize — you must recognize — in this business supports the reader.
Readers are the only people who absolutely deserve respect and courtesy. You must respect them by not writing down to them and by not putting your artistic flights above their need for information and entertainment. In other words, whether you believe you're working for an editor, publisher, an agent, or yourself, you're really working for those persons who pick up your story looking for something that serves them.
Ultimately, it is the writing that counts. Be faithful to the writing and to the people who read it. That's the ultimate in professional courtesy.
Write to share, not lecture. Point out what's interesting and useful, and withhold what's not. Include nothing that reflects only the thoroughness of your research; throw out anything that has the feel of a "see-what-I-know" boast.
Be a storyteller. Even if you write nonfiction, your readers expect you to weave a tale — to present the information as compellingly as possible. Be considerate enough to fulfill their expectations.
Answer all your readers' questions before they get a chance to ask them. Examine everything you write and ask yourself, Is this self-contained? Does it raise additional questions? Is it too general, which would leave readers craving specification or clarification, or is it maybe too detailed, leaving readers wondering why you were so exhaustive? Is the advice you give concrete and specific, allowing readers to put it to immediate use? Must readers dig further to put your advice to use?
Be honest with your readers. Don't twist or mold facts to fit the story. The tiny lies that fall out during such twisting will accumulate into a monstrous — and deserved — lack of credibility.
Don't withhold facts, either by design or by failure to do proper research. And don't elevate any particular fact, event, or subject beyond its actual importance simply to make a story more interesting. In fact, work to put your subject in its proper perspective, not only in its world, but in the readers' world as well. Ask yourself, "What does this mean to my readers?" Then tell readers your answer.
Much of this depends on your motive in writing about your topic. To promote it? To satisfy your own interest in it? To benefit the reader? To benefit yourself? Honestly assess the subject's perspective in your world. Ask yourself, "What does this mean to me?" Then, if appropriate, tell readers your answer.
Write as if speaking to peers, not as if playing cootchy-coo with children — even if your readers are children. Your readers are your equals. You are doing them no special favors by committing your thoughts and findings to paper; they could accord you similar favors — they could teach you as much about their worlds as you can teach them about the worlds you as a writer live in, explore, or create. You simply have earned the right to use the print forum to reach other people. In fact, you should feel privileged that these people have found some time to spend with your writing. Don't waste any of that time.
Include words and phrasings that communicate; eschew those that tickle only you and your pride in being a writer. Also, don't distance readers with formal, uppity phrasings. This writer sees no use for the phrase this writer — I is clear enough. And leave one out of it; talk about you. Extend a friendly hand and draw readers into your writing.
Write in the same language the readers read. Dropping foreign phrases indiscriminately into a manuscript is a faux pas — that's a weak joke, I know, but it makes its point in that faux pas is a phrase common enough to have given up its green card in favor of full citizenship. Most other foreign phrases have not. Deport them from your writing.
The same goes for dialect. Give us jes' a few words of it now, hear? A taste. No more.
Experiment for the sake of literature only with the understanding that experimental writing doesn't invite experimental reading. If your readers accept and enjoy your experiment, fine. If they don't, that's fine, too. Don't accuse the readers of failing you. You — or, more accurately, your experiment — have failed the readers. And that can be true even if your experiment, in your eyes, succeeded.
Don't deliberately try to confuse readers. For example, identify the people you're writing about, whether they're real or fictional. Don't just refer to them as he or she for three pages and figure that you are building mystery about these nameless people.
Don't take readers on a visual roller coaster ride that has them referring to chart upon chart or flipping to a glossary at the end of the book or leaping to the bottom of the page to inspect footnotes.
Play fair with readers, especially if you're writing novels or short stories. Fiction readers want to be coaxed into believing your fibs, but they don't want to be tricked. Don't pull surprises, like reluctant rabbits, out of your hat. Don't rescue the heroine with a cavalry-esque arrival of the heroic element, whatever that might be. Don't have the hero wake up to find the whole story was a dream. Those sorts of ploys aren't fibbing; they're cheating. And cheating is just plain rude.
In sum, honor your readers, your writing, your profession, and yourself by writing as honestly and as interestingly as you can. Live up to your readers' trust in you, while simultaneously making the reading experience as enjoyable and as comfortable as possible. Welcome readers into your manuscript as you would guests into your home. Entertain readers as you would friends at a party. Live up to their trust in you. Comfort them and joke with them and soothe them and make life a little easier and more enjoyable for them. And have a little fun yourself.
If you do, the readers will, like the good friends they've become, return to you again and again.