One of the fundamental rules for the behavior of any man who has the faintest pretension to being a gentleman, is that never by word or gesture must he compromise a woman; he never, therefore, writes a letter that can be construed, even by a lawyer, as damaging to any woman's good name.
His letters to an unmarried woman may express all the ardor and devotion that he cares to subscribe to, but there must be no hint of his having received especial favors from her.
Don'ts For Correspondence
Never typewrite an invitation, acceptance, or regret.
Never typewrite a social note.
Be chary of underscorings and postscripts.
Do not write across a page already written on.
Do not use unmatched paper and envelopes.
Do not write in pencil—except a note to one of your family written on a train or where ink is unprocurable, or unless you are flat on your back because of illness.
Never send a letter with a blot on it.