I'll bear these in mind:

3. Never use a verb other than ''said'' to carry dialogue.
7. Use regional dialect, patois, sparingly.

And this beautiful nugget:

8. Avoid detailed descriptions of characters.

Which Steinbeck covered. 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.

More here.