After reading about storytelling, I realized that I'm as fascinated to a well-crafted world as good plots and characters.
There's not much to read about, as a fiction world can contain as much detail as the real world. I'm spending time looking at the fiction worlds that I like and taking them apart.
As an exercise, imagining places and races is also interesting. You'll be amazed by the amount of details required to fill the gaps in order to "see" something in your head.
NK Jamisin (3 time Hugo winner) talks about world building as a technique. It's something mentioned in this great video about why "The Expanse" is awesome: https://www.youtube.com/watch?v=cGIovBe7pL8
You would probably have fun building a hard magic system. Hard magic being a system that has strict rules for how things work. Soft magic being Gandalf style where how it works and how it's limited is unknown.
One thing I've been thinking about recently is conservation rules. are there any popular fiction worlds that explore conservation of e.g. magic? The only example I presently know about is https://www.hpmor.com/chapter/78 (search for "conservation").
Most authors will sacrifice some amount of "realism" in the interests of story-telling (compared to Yudkowsy with HPMOR at least). A couple of Magic examples come to mind:
* Brandon Sanderson does a lot of Magic impacting Physics. The magic is often proper unexplained magic - but it's impact on Physics is pretty well modeled. In the most recent Mistborn book - there's a remark that explains that when the character magically reduces their weight while flying through the air - their velocity increases. I think Brandon points to that - but says that he loves the consequences at that level - getting to the point of red-shift/blue-shift for bubbles of fast/slow time is story breaking. See also his laws of magic: https://www.brandonsanderson.com/sandersons-first-law/
* Pat Rothfuss in the Kingkiller chronicles has a magic called "Sympathy" where rule 3 is "The law of conservation".
Although "unknown magic" and "ancient powers" are convenient, it bothers me to think there's no consistent system underneath it.
In the setting of the world, people in the world can view it as unknown, but the author is the god and should have a decent idea of how everything works.
I've done a few world building workshop and magic-system designs[1] workshop in a "nerdy-community centre" a few years ago. The community and interest for this is generally pretty small.
I was thinking about doing an interactive online version now that we're all stuck inside.
If you speak French, there is a conference by one of Ubisoft's creative directors about the Might and Magic world building techniques and choices on the BNF's Fantasy podcast.
Yep! A recurring hobby of mine is writing about a not particularly deep universe I was fond of in my teenage years. World-building my own canon so to speak.
Although you said there is not much literature around the subject, did you find anything? This has always been one of my favorite aspects of The Elder's Scrolls and, of course, Tolkien.
As a reference book, the Planet Construction Kit is good and comprehensive.
Although reading reference books like this can be a bit dry, it helps you recognize the elements that an author makes up for his or her world when you see them.
After reading about storytelling, I realized that I'm as fascinated to a well-crafted world as good plots and characters.
There's not much to read about, as a fiction world can contain as much detail as the real world. I'm spending time looking at the fiction worlds that I like and taking them apart.
As an exercise, imagining places and races is also interesting. You'll be amazed by the amount of details required to fill the gaps in order to "see" something in your head.