Dm advice for world building

So I’m a new DM I’ve been playing DnD for almost 2 years and I wanted to try being a DM for longer campaigns, I’ve hosted a few one shots of homebrew stories of horror and some other genres but I wanted to see what other people with a lot more experience than me could offer as advice, I know I could make all this easier and use the story’s provided to us but I find a lot of enjoyment writing out entire worlds with conflicts, secret societies, great evils that loom in the shadows, so I wanted to see what motivates you guys and where you get inspiration from for locations and characters in your games

Thank you for any advice you can give me!

I apologize in advance if this question is not in the right Subreddit mods please delete if not allowed