Story is more important than Setting.
This is one of the most valuable insights I ever learned as a new writer. No matter how incredible my world may be, how intricate and wondrous the characters, or how thoroughly amazing it feels to me, showing it off without purpose is a failure of my imagination. At best, the story will be little more than a travelogue for an imaginary world. At worst, it flaunts my lack of ability to fully realize the world I spent so much time building. The world should stay in the background for the story my characters and their conflicts bring to life.
This doesn’t mean I skimp on description or details. Those elements should serve the needs of the story, not dominate my narrative. Amazing depictions of imaginary worlds captivate us because they mold the action, or add to the emotional impact of a story. I don’t love Tar Valon because of the White Tower, but because Egwene rose to Amyrlin and repaired the breach in the divided Tower. The Mississippi isn’t a fond part of my memories of The Adventures of Huckleberry Finn because it was dangerous, but because Huck and Jim faced those dangers together.
Effort without purpose is wasted time.
World Building takes a good deal of time and effort. For me, it’s a layered process that includes rewriting sections of the world for the needs of the story. But at each point in the process, each decision as I weave the world together, the story always takes precedence. The coolest idea I’ve ever had won’t make it into a story if it doesn’t serve to bring the audience closer to the characters or conflict.
The opposite is also true, great ideas often propel conflict and deepen our grasp of characters. Luke didn’t want to be a moisture farmer, but he couldn’t abandon his aunt and uncle after all they’d done for him. The Poltergeist wouldn’t have even bothered Carol Ann if the Freeling family’s new house wasn’t built on a cemetery. The story is my focus, not my elaborate setting. No matter how much I love it or how excited I am to show it off to my readers.