I once employed a copy editor to edit a manuscript of mine, and he sent me a style sheet with the finished edit.
I've copied the relevant section below, scroll down to the bottom.
PUNCTUATION
ellipsis: 3 spaced full stops (non-breaking spaces between the stops)
parenthetical dash: spaced n-dash
quotation marks: double outer, single inner, conventional placement for dialogue; single outer for other uses
serial comma: no
DATES AND NUMBERS
zero to ninety-nine; 100, . . . (but all numbers spelled out in dialogue)
ABBREVIATIONS
no full stop after contractions (Mr, Dr, St)
PERMISSIONS
REFERENCE STYLE CODES
[TS – . . .] typesetting notes
- deliberate line space (between sections and between chapter heads and text)
ELECTRONIC FILE NAMES MISCELLANEOUS
Ellipsis to indicate trailed off speech
m-dash to indicate broken off speech
Hope that helps.
