“So it’s always critical to keep in mind that there are no rules in fiction, only conventions that have been built up over the years based on the way that writers have crafted their stories. (A convention is ‘an established technique, practice, or device,’ according to Merriam-Webster’s Collegiate Dictionary.) Conventions can be useful, because they provide successful models we can emulate and learn from, and which help guide us in the reading and writing of fiction. But too many beginning writers translate them into hard-core rules that must be followed.”

–from Alice LaPlante’s Method and Madness

Consider these other commandments/conventions in addition to those LaPlante mentions. And these. And these also.