Heres a list of things that you should think about when creating a new world/society for a story concept. They arent in any order. This is more of my college wisdom by the way.
1. The Time Period
Especially for a human society on Earth. Do your characters live in medieval times? Elizabethan times? Prehistoric times? This will greatly affect many aspects of the characters in the story, such as their clothing, posture, vocabulary (I mean really youre not going to hear the word dude come out of a French aristocrat), rituals, law enforcement, etc. Do your research.
If your characters live in the present day, invest in a fashion magazine and a hairstyle magazine and try to keep up with the latest clothing trends.
2. The Worlds Geography
Making a map of your world might help, especially if youre intending on writing a story that involves a character going on an epic adventure that takes them all around the world. Of course you won