Insecure Writer's Support Group, where on the first Wednesday of the month we vent our frustrations and fears to the world. This months' question is: "What writing rule do you wish you’d never heard?"
All of them. All rules can be broken. Can't write in dialect? Tell that to Irvine Welsh. Can't use adverbs? Tell that to J.K. Rowling. Can't kill off major characters over and over and over again until your readers scream for mercy? Tell that to George R.R. Martin.
Can't make a living writing? Tell that to me and thousands of other people.
There are no rules, only guidelines that can be bent if you figure out how to do it right. The idea of there being writing rules comes out of high school and college English classes, often taught by people who haven't written very much. Writers have to unlearn all this nonsense in order to get ahead. Author Dean Wesley Smith has done a brilliant series of blog posts called Killing the Sacred Cows of Publishing that's well worth reading. I don't agree with everything he says (otherwise there would be no point in my reading him) and I do think he overstates his case in a few places, but on the whole I think this blog series makes excellent reading for all beginning and mid-career writers.