Fiction Writers Rules

1. Avoid repeating words in a paragraph. It reads poorly.
2. Spelling errors are unforgiveable. Spellcheck is F7. Fix it.
3. Never EVER begin a character dialogue with the phrase "I know." It grates. It's childish, and a sign of immature writing.
4. Its and it's are not the same. Watch out for that.
5. Avoid creating a Mary Sue character. Conflict is drama.
6. Get a beta reader if you can. They will spot errors you missed and notice mistakes you made.
7. Remember that villains are smart too. Stupid villains aren't worth reading. Stupid villains are crap writing.
8. Avoid shopping lists. Boring.
9. Avoid shower and toothbrush nonsense. Unless it's really important to the plot, you just marked yourself an obsessive idiot.
10. Show don't tell. Break up any exposition. Too much "because" is a sign of Aspergers.
11. The reader is the 3rd part of the conversation, so what the reader can infer doesn't need to be said.
12. Recounting already described plot is not only useless, but a huge turnoff to readers. They read it already. Just say "He briefly explained what had happened" and move on. 
13. Every page must be interesting. If more than a couple paragraphs are dull, the reader will skim. If the reader skims more than one page, odds are they'll drop the book entirely and avoid your work in future. You can't afford to lose readers. It is better to cut/edit out boring material than lose readers.
14. Write first, edit later. They are different processes and your mind needs to be in radically different places. A first draft is just a first draft. Editing and fill and more editing can come later.
15. Get in the head of your characters, even the villains. Give them logical reasons for their actions from their perspective. Good writing and dialogue should flow from this. Worry about accents later.
16. Remember the 5 senses. Poor authors forget most of them, but a good author mentions them in each scene. The more senses, the move evocative and immersive the writing, the better it reads, provided details don't overwhelm the plot pacing.
17. Pacing matters. Sometimes you must leave out details or barely mention them to give the reader a sense of things moving faster and faster.
18. Mind your word choices. Many readers find reaching for a dictionary to be annoying.
19. Writing below the level of your readers also turns them off, so pick your writing vocabulary on the same level as your readership's education. Note that many bestselling authors write for high school graduate level readers.
20. Promoting your books is your responsibility. New York Publishing Editors are parasites and don't really care about your work. It is up to you to promote your books because publishers won't, and those who do, CHARGE AUTHORS MONEY FOR IT.
21. Self publishing via print on demand is the way to go. This is more work for you, but far higher profit and lower cost books FASTER. Organized publishers average 2 years from submission to books on the shelf. If what you are writing is a timely subject and will be boring in 2 years, you MUST self publish via Print On Demand to have any hope of a viable audience and sales.
22. Learn enough web design to make promotions for your books to drum up interest. And despite being a writer, a picture is still worth 1000 words, so Flicker is probably a good idea, and referencing your work to gain attention and readers to buy your book, chapter by chapter, will pay for itself.
23. Depending on the genre, you may need to promote your books at Conventions. Get used to travel and do the taxes to write these costs off as a business expense, which it is.
24. Be friendly with the fans, and understand the service you provide is helping them live fuller lives than burger flipping or code editing. You are saving empty lives from suicide in the modern horrible economy.
25. Keep tabs on what interests your fans, research these topics thoroughly, and write about them in your books in a way they like, including plausible or factual details from experiences either share or want to know about beforehand. Fantasy novels are about self gratification and affirmation, after all.
26. Every opinion you issue will offend someone. Be careful what you say. This is particularly difficult when writing, so always preface convention answers with "The character" rather than yourself. Heroes can be villains, and villains are heroes that lived long enough to become them.