Observation vs. Logic

Two ways to give your book a more realistic feel; OBSERVATION and LOGIC

OBSERVATION

This entails things you've noticed from the world around you.

The way rain drops follow each other's trails when they go down the window, how sometimes mud has a layer of creamy mud on top, the sound of a broken vacuum, how rainstorms smell, how cats slowly twitch their tails, the way teenage girls walk.

LOGIC

This is based on cause and effect.

For example, if it rains and storms in your book, how does this affect the countryside? If there are rivers they will grow, trees may be knocked down. How does this affect your character?