Deciding where to start a new paragraph is important. Readers can get confused or lost if everything’s all in one. So, I made a list of the top three reasons to start a new one.
Who’s speaking changes
If a different character talks, start a new paragraph. Having two characters speak in the same paragraph will confuse readers.
Also, if one character speaks, put other characters’ actions in a different paragraph. Readers can follow a story better if one paragraph follows one character. Unless a lot of action happens all at once, mixing different characters’ actions and dialogue can get confusing.
Camera moves
In scenes, it can be helpful to think of it like you’re filming a movie. If the camera angle changes in any way, it’s a good idea to start a new paragraph. This smooths out the scene, keeping everything on one topic together.
Something major—like time or location—changes
If something big changes, it’s critical to start a new paragraph. Readers can get confused by a sudden change if it’s in the middle of a paragraph.
Bonus reasons:
Emphasis
If you’d like to emphasize a sentence, putting it by itself in its own paragraph is a good way to go. It makes the sentence pop off and stick out to the readers.
Dialogue takes up most of the page
If dialogue spans over half a page, it may be a good idea to split it up into multiple paragraphs. Having long blocks of words can get hard to read for some readers.
Hope this helps!