Above all else, I read the types of fiction I write. which for the most part is classic novels, young adult/new adult and fantasy. This means that I try to stay in my lane when it comes to writing what I love because I draw a vast amount of inspiration from what I read. I don't write romance, I don't write crime, I'm even on the fence about Sci-fi because it's so different from what I read.
The reason I do this is that, while there are several fantastic books on the tools of writing good fiction which I will list below, our training is only found in the reading of other works for comparison and competency. John Green, a fantastic young adult novelist said it best. "It's the only apprenticeship most of us have."
That said stories don't just show up to be written and if they do they are often incomplete for a good story. there is a reason that most of the top blockbusting movies based on books have a similar if not the same plot and story structure loosely based on the hero's journey.
Plot matters as do the devices that work in it and as a writer knowing these means the difference between having an awesome idea and writing an awesome book.
As such the bare minimum pre-requisites for writing fiction are as follows.
101:
-Mandatory 100 fiction books read, to get your bearings on what you're going to write. you are going to enjoy some and hate others put in the work, get those books read.
-A monthly reading of "The Elements of Style by Strunk and White" for a sharpening of the use of the English language in prose while you start.
-A mandatory keeping of a note-taking system of either a notebook, cloud-based app or stack of 4x6 index cards. No thought or idea is so trivial that it can't be written down.
-The fastest pen you can afford and bear to loose when lent or stolen,
201
-The purchase of a matching set of dictionary and thesaurus. Don't use a digital source, the switch to picking up the book will activate different parts of your brain and help figure out what you were looking for.
-Reading of Stephen King's "On Writing" to see what an author's life can look like from start to healthy middle.
-The establishment of a weekly digital back up of all drafts and source material. 2 is one and one is none, your work should be in three places at all times.
301
-Participation in NaNoWriMo, National Novel Writing Month, in November. This will squeeze a rough draft out of you and give you first-hand experience as a writer who needs to put down words in order to make deadlines.
-Outlining consisting of the bare essentials of at least 5 books, to teach you how to plan and process your ideas.
And that right there will get you started into the wild wild world of fiction writing. there are a million variations on the themes and even more ways to skin this cat. I am the least qualified person to give advice past this as I have one published fiction work and 4 in draft. But this is how I approach writing stories. I hope it helps.