I always wondered this. Amir makes when to start a new paragraph in fiction clear!
For fiction, you’ll construct your paragraphs for setups, punches, and other desired effects. For example, the one-word paragraph.
THE RULE: Always start a new paragraph when you switch speakers in dialog.
GUIDELINES: Start a new paragraph when
1.a new character reacts or does something,
2.a new character thinks something,
3.a new idea enters,
4.a new event happens,
5.a new setting occurs,
6.the reader needs a break from a long paragraph,
7.the “camera” moves. Ray Bradbury suggested, as in movies, every time the camera angle changes, start a new paragraph,
8.a portion of information isn’t closely related to another and needs to be distanced,
9. a change in emphasis or tone is needed in a topic,
10.the time moves forward or backward,
11.a description of one thing ends and something else is described,
12.a special effect is needed to add humor or drama.