Character BUILDING and world BUILDING are private functions you carry out. Then in the story itself you do character REVELATION and world REVELATION. Building and revelation are two separate functions.
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I love making new characters and expanding on the world I've built, but it's essential to have a good balance. Having the characters explore the world, or even just be aware of it, is better than just like...an information dump. I've been building my fantasy world for....too long. Not even the world, just one country in this world. It's the country where everything happens, but still.
Also, for world-building so I have a better idea of everything, maps are kind of a godsend. I LOVE looking at maps for writing. If it's not in a world that's relative to our own, making it so I can't look at maps, then I just make one myself. It gives me a better idea of how everything is seen through my characters' eyes. It also gives me a better idea of why and how people from different areas so different. For example, my country is made up of what essentially used to be 4 smaller territories, but most people don't really go to 3/4 of these areas unless they live there. When I built a map my reason for that went from being 'it's hard to get there' to 'one of these places is a big ass desert, there's a huge, difficult to navigate mountain range around the other, and the last is just cold snowy wilderness'. I already knew this, but a map just made it easier to articulate. MAPs!
side note, if you want to make a map, I suggest inkarnate.com, not because it's the best map-making platform I've used, but because it's the ONLY mapmaking platform I've used and it works really well for my needs. I'm sure there are others, but that's just mine. And it's free if you don't wanna pay for it. I mean, I paid for it because I use it all the time, but you don't have to pay for it.