I'm frequently bewildered by the pronouncements made by those who label themselves grammar experts. You know what I mean. Here's a random sampling of some I've actually heard over the years.
There's no such thing as a misplaced participial phrase, and I know because I'm a grammar queen.
You must begin every paragraph with a topic sentence. Even dialogue paragraphs need topic sentences. Trust me. I'm a grammar nerd.
I majored in English and I know what's what. You should begin every fourth or fifth sentence with an adverb to vary your sentence structure.
The simple truth is that blanket rules like these rarely apply in blanket form to fiction. (Even if they were true rules, which they are not. Please don't anyone decide to start every fourth sentence with an adverb because of this post.)
Grammar is a complex system of rules that can be loosely broken into two schools of thought.
School One: The Classical Approach
According to this philosophy of grammar, rules exist to create and enhance clarity. We all adhere to these rules because doing so makes communication easier. The rules are the foundation upon which communication is built.
If in school you diagrammed sentences and analyzed the placement and content of phrases and clauses, then you were exposed to classical grammar. If you attended school prior to about 1980, most of your English grammar probably was made up of this approach.
School Two: The Generative Approach
According to generative grammar principles, the constant evolution of spoken English means that our grammar rules are in constant flux. Grammar rules are formed by listening closely to the way people speak and then by finding the principles that form the basis for the speech. In other words, the communication is the foundation upon which the rules are built.
Generative grammar has been with us in some form or another for a long time (see Mark Twain and Ernest Hemingway for examples of novels that take more generative approaches -- but keep in mind that generative rules change with time and slang, etc.), but it became a larger part of the classroom zeitgeist starting around the late 1970s. If you were told to put a comma wherever you need to pause for breath in a sentence, you probably learned at least some generative grammar.
So what's a fiction writer to do? Which philosophy should you adopt? The answer is neither, and both, and either, depending on circumstances.
The Third Approach
Have you heard of style guides or style books? These are internal documents created by a publishing house to guide its writers and editors in its proprietary fictive grammar. Fictive grammar is a flexible set of principles which draws on both generative and classical principles to create a platform which varies from house to house and from imprint to imprint. Because style guides are proprietary documents, you probably won't be able to find out the particular platform adopted by a house until your manuscript is under contract.
But there are general guidelines you can follow which will help you when correcting your own manuscripts for grammar.
First, keep in mind that some elements of grammar are less mutable. Verb conjugations, formation of participles, placement of adjectives next to the nouns they modify -- these are all solid rules. Don't break them.
Second, most style guides allow greater flexibility (that is, a more generative approach) in dialogue and in interior monologue. Taking this a step further, if your manuscript is written in a very subjective form of point of view (such as first person or third person stream of consciousness), you have much more flexibility throughout the entire manuscript. Conversely, if your story is told from a more objective point of view, you're better off sticking to more formal English rules.
Third, some things can be learned from reading. Try this experiment. Pull a current novel off your shelves. Scan it for ellipses. Are there any? How frequently do they appear? Are they only used in dialogue or interior monologue? If they appear at the end of a sentence, do they take an end mark? These are just some of the questions a style guide might address for just one of the more slippery areas of fictive grammar.
Fourth, be consistent. If you use a comma to offset an introductory adverbial clause in one sentence, you should do it in all of them. Decide on your own personal rules, and stick to them, but keep in mind that your editor may change these details later so that your manuscript meets house standards.
What's the bottom line? As important as it is for a fiction writer to learn grammar, it's just as important that you remain open to the possibility of another approach. And the next time a "grammar geek" tees off on you over some pet rule or other, ask them to explain their grammary philosophy. You might get a blank stare, or you just might get a fascinating glimpse into the mind of someone who has really thought it all through.