1) Never open a book with the weather
If it’s only to create atmosphere, and not a character’s reaction to the weather, you don’t want to go on too long. The reader is apt to leaf ahead looking for people.
2) Avoid Prologues
They can be annoying, especially a prologue following an introduction that comes after a foreword.
3) Never use a verb other than “said” to carry dialogue
The line of dialogue belongs to the character; the verb is the writer sticking their nose in. But said is far less intrusive than grumbled, gasped, cautioned, lied.
4) Never use an adverb to modify the verb “said”
… he admonished gravely. To use an adverb this way (or almost any way) is a mortal sin. The writer is now exposing themself in earnest, using a word that distracts and can interrupt the rhythm of the exchange.
5) Keep your exclamation points under control
You are allowed no more than two or three per 100,000 words of prose.
6) Never use the words “suddenly” or “all hell broke loose.”
This rule doesn’t require an explanation. I have noticed that writers who use ”suddenly” tend to exercise less control in the application of exclamation points.
7) Use regional dialect, patois, sparingly
Once you start spelling words in dialogue phonetically and loading the page with apostrophes, you won’t be able to stop.
8) Avoid detailed descriptions of characters
In Ernest Hemingway’s ”Hills Like White Elephants” what do the ”American and the girl with him” look like? ”She had taken off her hat and put it on the table.” That’s the only reference to a physical description in the story, and yet we see the couple and know them by their tones of voice, with not one adverb in sight.
9) Don’t go into great detail describing places and things
Even if you’re good at it, you don’t want descriptions that bring the action, the flow of the story, to a standstill.
10) Try to leave out the part that readers tend to skip
Think of what you skip reading a novel: thick paragraphs of prose you can see have too many words in them… I’ll bet you don’t skip dialogue.
Elmore Leonard’s #10RulesofWriting