· Anyone can write a book. False! If that were true, there would be a lot more books out there (and the number of books out there is still mind-boggling). It's not just a question of talent, either: as I've said before, patience and discipline are crucial to the process. So is luck, but since you can't work on that, work on your writing—everything from mechanics to your work schedule (and you need a schedule).
· It's all about who you are/what the hot trend is/&c, i.e., writing doesn't count. False again! It's all about the writing, cats & kittens. Sure, if you happen to be writing about The Cool Thing of the Month, that may help you out. And if you're already a celebrity, that'll grease the proverbial wheels, as well. And, well, yes, there are some really well-written novels that get passed on every year because they're simply not salable (too long, insufficiently large target audience, &c). But fundamentals are fundamentals: without strong writing, you're almost certainly not getting a contract.
· You have to be a tortured single twenty-something to write a book. Not true! You can be a tortured fifty-something lawyer with nineteen kids, or a tortured single mom working at a truck stop in Ohio. (I kid about the tortured bit, but you get the point.) This ties into the point about writing schedules (above), but it's simply not true that you can't make time to write unless you have no spouse or dependents or twelve-hour-a-day job clamoring for your attention. Making time to write is part of being a writer. Period.
· You need an MFA to write, or at least, to write literary fiction. This myth seems to be cropping up more and more lately—probably as a result of the recession driving record-high application numbers at MFA programs across the country—but it simply isn't true. Yes, there are people who benefit enormously from graduate-level work in creative writing, and a lot of the Future Hot Shot Writers of America will likely have MFAs from Iowa, Columbia, Michigan, Virginia, &c. And that is great! I'm not saying it's not. What I am saying is: thankfully, you don't need any kind of professional licensure to write. If an MFA makes sense for you, go for it (though I recommend you go for a fully funded one, since it's nonsense to pay through the nose for an art degree that will never earn out that investment). If not, don't worry about it. Keep writing.
· If you can't sell your first or second novel, you're probably not a very good writer. False again! This may sound like something I've said before, but nay—what I said was, "if you can't sell your book and have tried literally everything, and you've been ultra-professional about it and haven't even gotten a request for a partial based on your carefully crafted query, your novel is probably not very good. Write another." Not that you aren't good, fair readers, just the novel. And yes, as I noted above, sometimes it's a great-yet-unsalable novel, but this is relatively rare. You may get lucky and publish the first novel you ever write, but more likely it will be the second, or fifth, or tenth. Write, revise, polish, query, repeat as desired.
· Just because you can write a great novel doesn't mean you can write a good query letter. Of these, this is the one that's likely to get most of you up in arms, novelistos and -istas. However, I strongly believe that if you can write a really kick-ass book, you can write a good query letter to advocate for it. Granted, I don't think anyone naturally knows how to write a query letter—it's a kind of discourse that has to be learned—but if you're a good writer who has time to do the appropriate research and put in the necessary time, there's no reason it can't be good. (Caveat: I am a big supporter of the "submit the first few pages with the query" method to ensure that the minority of great writers who can't query worth a damn don't get immediately passed over.)
· Writing can't be taught or learned; it's an innate talent. I won't deny there's talent involved, but if writing can't be taught or learned, I'm not sure what's going on in all those seminars/workshops/MFA programs/creative writing classes being held and taught all over the country. Your writing can and will improve with time and practice, so long as you're reading good writing and are open to learning from other writers (both published and aspiring). Set time aside to read, to write, and to learn from mentors and peers. I can't guarantee it'll ever get you a book deal, but it will make you grow and improve, and that—BIG REVEAL, dear readers—is the second half of the battle.
The first half, of course, is knowing (see tag).