>>53444726I'm that guy above, and I'd be happy to share my experience and how I generally go about it.
As for what drives me, a log of hags and fantasy bullshit. I've always loved fantastic adventures, magic spells, and overcoming the odds with friendship and love. It charges me up like nothing else.
For the world itself, like all stories, your world needs a starting point. For the characters you want to introduce and work with, what kind of environment would be suited for the beginning of their story and what their initial motivations, personality traits, and even their past experiences. When I first started making HoloJourneys, I had an idea for what the initial world state would be like, and from there I started listing out potential governmental powers and countries. For Hololive girls, I try to focus on what their cultural background would be within the world and where/how that would fit in best.
Girls with either lore relating to being royalty, or outfits that present them as such, make it easy to give them their own kingdom: Lunahime is practically a free space. Pekora you take a few liberties thanks to her princess outfit, but through her content she gives a lot of lore for fun about Pekoland and how she rules it. Then you got chuubas who can be used to showcase a smaller culture within your world. Kaela is a good example of this, as you can easily plug her into a smaller and less advanced culture compared to others, that has its values heavily set in hard work and living off the land. She is a penguin though, so they might be living somewhere colder.
For organizing, there's kinda this notion of what the Anon and friends know of the world, and what you the writer know. I currently know what kingdoms and lands are coming up, but anon himself only knows what's in front of him and where he's been, so you almost end up connecting the dots together in a sense. Since I spend a lot of time writing about each area, they just kinda stick in my head. Also the content of your story itself helps shape the world you create. Some things kinda end up appearing and falling into place.
I hope that helps you a little bit. Let me know if there are any points I could be more clear on, or other questions you might have. I love talking about this stuff and helping anons get their writing hands moving.