First, I want to talk a bit about the philosophy of philosophizing about storytelling. You might think how good a story is is subjective, and I can't claim a story is bad just because I didn't like it. But if you believe that then what's the point of even talking about this stuff? If the quality of a story is subjective, then all this talk about the way any element of a story "should" be is meaningless, so what are you even doing on this page? Now that we've cleared that up, here's my repository of advice.

Storytelling generals

What makes a good Chapter One
What makes a good plot
Tragedies
Themes of a story

Worldbuilding

What makes a good world
What makes a good magic system
Fake Sci-Fi - extremely common worldbuilding mistake

Characters

What makes a good hero
What makes a good villain
Strawman Chaotic Evil - trope to avoid
The Omniprotagonist Fallacy

Plot events

Time Skips and why they're dangerous
How to rescue a character without taking their agency
Portraying extreme emotions
The Last-Second Rescue trope and how to avoid it
How to make good moral dilemmas (for characters)
How moral choices in video games (for the player) could be improved

Messages of a story

Messages: Your story has them, how to notice and control them
Glorification of characters
Sexist tropes