Bill Brohaugh once declared that the only reliable rule in writing is "Never start a sentence with a comma."
So far I haven't had cause to question that one. You also probably shouldn't start with periods, colons, or semicolons, either.
[Warning--pointless digression contained in these brackets. In Spanish, of course, you can start a sentence with a question mark (upside down), which has always looked to me as if the writer wasn't merely asking a question but was vastly, urgently confused, and perhaps a touch overwrought:
¿What was that?
¡Spanish can also start with an upside-down exclamation point!
And, although it seems unlikely, when you have a question that is also an exclamation of surprise, you are supposed to use the inverted bang at the front and a question mark at the end:
¡Why on earth am I writing all this?
In English, of course, if you're James Joyce or Alan Paton writing dialogue, you can even start with an em-dash. But commas, periods, colons, and semi-colons make a poor start to a sentence, and that's an iron-clad rule.]
My problem with rules about writing is that they generate in my writerly ego an overweening desire to break them, just to show it can be done successfully. "Never open a story with a dream." Ha. Done that, and the book will be published next year. "Never have a villain whose only motivation is that he's 'evil'." Done that, too, and he's my favorite villain. (He's a god who feeds on anguish. It's his niche in the metaphysical ecosystem. It's not a bwah-ha-ha-ha sort of thing. It's science.)
I know this attitude of breaking things becasue they're there is contrary and childish. I have my own rules (I don't put adverbs in dialogue tags, for example), but they are part of my little personal code of conduct, not something I assume to be universal. And whenever I'm exhorted to follow some precept as a necessary key to readable writing, I dig in my heels.
Here's one I've heard a lot lately: Tension on every page. (Lit agent Donald Maass--a very good agent--is usually credited.)
Do we really need tension on every page? I don't think so. I can point to many pages in many great novels that I would say are totally devoid of tension. And while writing I certainly don't stop every hundred words and ask myself is there something I can do to ensure there is tension on this page?
Of course, one of the things you quickly discover is that the adherents of such rules tend to engage in redefinition. Show them a passage where the author has clearly succeeded in maintaining the reader's interest despite the fact that it's a scene intended to show that the characters have arrived at a moment of safety and comfort, and they will reply--ah, but that's the calm-before-the-storm, a classic kind of tension. Show them a funny scene, a tender scene, a lyrical scene, and they'll find tension in there somewhere. Basically, in their view, Interest = Tension. It's like arguing with a religious fanatic--everything that agrees with them proves their point, and so does everything that contradicts them.
This redefinitionist tendency results in some pretty silly situations. I've seen people assert that all first-person narrators are the protagonists of their novels, and then watched them try to wriggle their way through to demonstrate their theory, rather than simply conceding that their idea was a little flaky. (I don't know how the hell they try to prove that Watson is the protagonist of the Sherlock Holmes stories, but I'd like to watch them weasel through that one.) But that's another complaint, and I shouldn't get distrracted from my current diatribe.
Why do I care about this tension contention? Partly just that childish streak, and partly because I've seen too much amateur writing lately that is clearly striving to put tension on every page, and it gets damned annoying to read.
Novelist and teacher Raymond Obstfeld sets a goal I find more reasonable--a gem on every page. Might be tension, might be language, might be a perfect line of dialogue, might be just about anything that makes the reader glad they read that page. Make every page sell itself.
Now there's a rule I can endorse (if not always succeed in obeying).