I'll put it this way--no one wrote a beautiful story the first time. There was probably a ton of rewrites over months and years before they honed their story into what it became, not to mention years of practicing.
I won't call myself a master storyteller, but I used to write a lot as a teen and I'm trying to rekindle that spark after years of inactivity. Here's what I'm doing:
- Make a document listing all your world-building/research, include character sheets as well
(traits, strengths/weaknesses, backstory, motivations-what are they trying to achieve in the story)
- Make an outline of your plot. You don't have to be super detailed, just figure out the flow of events and get the base story out of your head.
- For chapters, list a few of those plot points and add descriptions of settings, characters involved in the scene, dialogue and descriptions. Start building them up until a scene is fleshed out. This is where the work occurs and it may not happen as quick as you want it.
- If you get stuck on a thought/action/description/event--SKIP IT, and write around it. You can go back and figure out what you want to say later. Epiphanies happen alot outside of writing, and editing.
- (This next one may take some experience, and deep character-building which you may not have at the beginning of the story which is okay for beginner writers, so you can drop this one if it's too much thinking, but ideas may come when brainstorming the deep stuff)
If you're not sure where a scene is going or what it's purpose is, try to come up with questions and answer them via yourself or your characters, just to validate why you're writing the scene. What is the character trying to achieve learn from this scene/dialogue? Does it change the character? If so, how? If not, why? Think of it like a quiz at the end of a chapter. If for some reason you can't answer the questions, then the scene may not be needed - unless you're doing it for fun, which is fine too! Not everything one writes needs critical thinking, just adds depth.
- Read more into the genre you want to write. Note any patterns you notice (word usage, metaphors, etc) and try to implement some in your writing, and see how you can build up your own voice (not copying, mind you, but logically think about their writing style like a critic/English teacher and learn from them, if you can)
I'll admit this list is--weirdly complicated, sorry. But like anyone else, it's best to start somewhere (I'd advise trying the first three/four and see how much writing you can generate at the minimum level). You can always fix/edit/embellish things in another draft. Nothing is perfect.
If you write a little every day, you can train your brain into writing for you.