How do you build a rich world regardless of genre?
1) Ground your characters. Tell the reader what their feet are touching - cement, mulched path, gravel, brick, asphalt. Give the reader an idea of what the air smells like, what the place looks like. Ensure you have the five senses. You don't have to be Michener with chapters of description. But if your characters are in a national park with wind and snow, tell me more. Are there trees? What kind? Are they on top of a mountain? Are their rocks at their feet? Campers nearby? Are they on a hiking path or in a meadow?
2) Clue the reader in on what is important to the characters. Why does she have an herb packet in her pocket. Why is she giving it to a little girl? Why are her dreams important. Who is the person they are chasing? Why are they worried what the council thinks? who is the council?
3) Remember that the hero's journey begins in the ordinary world. If you push them into the call to action too soon, the reader has no sense as to how that is different. What is at stake. Why the character would go on the journey.
World building involves setting, the five senses and character motivation. Without proper world building, it doesn't matter how colorful or magical your characters are, the reader will be lost and pages will not be turned.
My favorite story is when my New York Editors didn't understand the world of a midwest city. What is common place to me had to be explained in my story so that those who don't live in that area of the country can understand.
Have you ever been told you didn't world build enough?