I don't do all the background and the worldbuilding before I start the story. What I do is I work out the bare minimum I need to start the story, and often that really is a bare minimum - it's a character in a situation, and I know nothing about the character, I know nothing about the situation, and then I think about it for a long time, and make notes about where I think the story is going to go and so on, but I don't really make notes to do with the background or the magic system or the world.
Garth NixWhy, Yrael?โ it said, as the last of the dark gave way to silver, and the shining sphere of metal sank slowly to the ground. โWhy?โ โLife,โ said Yrael, who was more Mogget than it ever knew. โFish and fowl, warm sun and shady trees, the field mice in the wheat, under the cool light of the moon.
Garth NixBut think of how much worse it would be to sit here, not knowing. Until the Dead choke the Ratterlin and Hedge walks across the dry bed of the river to batter down the door.
Garth NixI suppose you could call me...Soot," said the thing. "Yes...Soot. I have breathed it, lived in it, and eaten it for so long that it is a fitting name." "Eaten it?" asked Suzy. "Why eat soot?" "Boredom," said Soot.
Garth Nix