Opening the book…
A world feels real in proportion to how much its events refuse to be undone. When a city burns, the ash should still be on the wind three chapters later; when a character crosses a line, the crossing should follow them. Fiction that lets its own catastrophes evaporate teaches the reader that nothing here truly sticks, and a reader who has learned that will never fully worry again. Consequence is how an invented world earns emotional weight, because grief, cost, and change are the proof that the world is a place things happen to and not merely a stage that resets between scenes.
After any large event, ask who is now different and how the world around them has shifted, then let those answers ripple forward into later scenes whether or not the plot requires it. Track your damage: the wound that should ache, the debt still owed, the trust not yet rebuilt, the season that will be hungry because the fields burned. Resist the reset button, especially the tempting kinds, the wound magically healed, the death revoked, the memory conveniently wiped, because each one you press quietly drains the stakes from everything after. Let time and loss accumulate, so the world at the end is visibly the sum of what happened in it.
Not every consequence needs to be permanent or grim; healing, mercy, and repair are consequences too, and a world with no recovery is merely bleak. The point is that change costs something and leaves a mark, not that the mark can never fade. Even a happy ending should be visibly paid for.