As a fiction writer, your goal is make the most perfect and smooth world possible. You want:
The natural world: When you describe the natural world, you are talking about what type of place your character is currently in. Natural world falls under the categories of geography, weather, and thousands of other details. In J.R.R Tolkien’s epic series The Lord of the Rings, it is very easy to understand the type of world they live in.
A. From early on you know it’s based on an old medieval world.
B. You know that the plains and mountains are rugged and dangerous.
C. You know that the inhabitants are deadly and pose a natural danger.
The Lord of the Rings is an excellent example of describing physical environment and planting the image in the readers mind.
The religious or cultural societies or groups: Say your book is based in a small town in the middle of the desert, somewhere in India. What kind of religion will be floating around there? Will there be assassins? Mercenaries? Hippy’s? You decide. The Harry Potter series by J.K Rowling’s is an excellent example. All of the students parents act and live exactly like wizards and witches in a strange magical community. Even the buildings and environment as described show what the groups are like.
Conflict: Do not forget the conflict. The only reason I mention this is because with out a conflict you have no chance of selling your book, if you plan to. Writing a book without a conflict is like buying a bunch of gas but trying to drive the car without the battery. A conflict is one hundred percent necessary.