When I worldbuild, it’s usually from a molecular level up. So I know the mineral content and geological makeup of each of my planets. Then I work out the gravity, and how long each one takes to make a trip around its sun. I work out the effects of tides on the land.
Sometimes I use a bit of shorthand. Usually for the towns and how they are laid out. Especially if, when I created the world, I didn’t think this part of it would be on show, so I haven’t got a streetscape, nor is it peopled.
Sometimes this comes back to bite me on the butt, and I get to spend a couple of days trying to decipher the shorthand I used several years ago, to fully create the town I now want to write about. A job that would have taken me maybe half an hour had I done it properly at the time …
*sighs* Past me sucks.