There are lots of ways in which learning to write is like learning to drive, but the relationship of the craft to the rules and laws is not one of them. Whether it's that you should Show and Tell, or that "cut everything which includes was" is not only wrong but dangerous, I don't believe you should "know the rules before you can break them", because there are no rules (except copyright and libel, obviously), only tools, in writing.
I've been talking a lot recently about writing historical fiction, and inevitably we discuss how you decide what you must research and what you can invent, what you must stick to and what you can change - whether imagining and changing things is because you can't find out what "really" happened, or because strict accuracy would screw up your plot or your readers' (albeit sometimes exasperated) love for your main character. [edited 10th June 2018 to add and exploration I did over at Historia Magazine, of the issues of cultural appropriation in writing fiction]
And since you'll be making these decisions at micro- and macro-level and all the way along, it's probably a good idea to extract the general principles, and make yourself your own little mental or physical "rule-book" for this project. An example of two such rules would be Margaret Atwood's, in her marvellous essay "In Search of Alias Grace" (which you can read online at JSTOR via that link) :
when there was a solid fact, I could not alter it […] Also, every major element in the book had to be suggested by something in the writing about Grace and her times, however dubious such writing might be; but, in the parts left unexplained – the gaps left unfilled – I was free to invent.
This kind of overall decision saves you working things out from scratch each time, but I think there's more to it than that - though I'm not sure I could prove it (or not without a year's research grant to live on while I did). I think that the reader unconsciously senses consistency and inconsistency, whether it's in you sticking to your quasi-rules about - say - inventing villages, but sticking to genuine geography for towns; or staying true to your overall decision about how "historical" you want the voice of your novel, and the voice of the characters. And readers also, and very strongly, sense (in)consistency in the "writerly" decisions about things like handling point-of-view, narrative tense, and psychic distance.
So don't try to persuade yourself that you don't need to think about these things beyond your own necessity, because "real readers won't notice". Yes, the vast proportion of a reader's response to a story happens below their consciousness, but that response still happens, as I explored in that post. As writers we've trained ourselves to sense our unconscious responses, and bring them up to the surface to be explored, and so we're a-typical in spotting typos, or sloppy handling of point-of-view or commas. But that doesn't mean that typical readers isn't affected by inconsistency, carelessness or bad decisions: it's just that the effect on them is to make them feel restless, or bored, or unable to keep to their side of John Gardner's "contract of fiction", which is forgetting that these things never actually happened.
Nor does "our book, your rules" mean you can ignore feedback. Of course you need to put individual pieces of feedback through your "Accept, Adapt, Ignore" scanner, but whatever the result of the scan, it may have implications for your overall rule-book. Does it? And "your book, your rules" doesn't let you off the hook of "write for your reader", either: the whole point of it is to help you work on your reader as effectively as possible. And that might well include thinking about what "rules" of your genre you're going to stick to, or not.
The Your Book, Your Rules, But Make Some principle has one more consequence. In the first fifth or so of a narrative form, the reader is busy learning how this musical/play/novel/film/poem works, but once they have (unconsciously) tuned in to the language-rules of this event, they will go on experiencing it in and on those terms. If you switch languages, as it were, the chances are they won't know what's gone wrong, but they'll notice unconsciously and be bored or uneasy. So you need a very good reason to change those rules, and you need to take the risks of doing so into account, and try to minimise them.
Which isn't to say, of course, that anything you put in your rule-book is unbreakable. I remember ploughing through the whole of A Secret Alchemy, trying to work out some rules for that often vexed question for historical novels: how and when and where and which contractions I might use. Didn't or Did Not? Can't or Cannot? Wouldn't have or Wouldn't've or Wouldna or Winna? What sounded too modern, what sounded too stilted, what was wrong for the dialect? Was it a matter of the particular words, the particular character, the particular region or the particular moment in the narrative? But whenever I tried to make myself a rule, I promptly came on an example where keeping it was "outright barbarous", as Orwell's Sixth Rule of writing puts it. And yet, as I worked my way through, reading each occurrence aloud, I did develop a sense of the most common combinations, and undeniably, the decision I made each time was a matter of the interplay of those different particularities - but the casting vote had to be the shape and rhythm of each particular sentence.
So maybe your rule book comes in two parts: the actual laws, which everything must conform to, and the Highway Code, which is all about best and accepted practice for most situations. Sometimes writing is very like driving.
