From a book called Hill’s Manual of Social and Business Forms, published in 1880.
- Never exagerate.
- Never point at another.
- Never betray a confidence.
- Never leave home with unkind words.
- Never neglect to call upon your friends.
- Never laugh at the misfortunes of others.
- Never give a promise that you do not fulfill.
- Never send a present, hoping for one in return.
- Never speak much of your own performances.
- Never fail to be punctual at the time appointed.
- Never make yourself the hero of your own story.
- Never pick the teeth or clean the nails in company.
- Never fail to give a polite answer to a civil question.
- Never question a child about family matters.
- Never present a gift saying that it is of no use to yourself.
- Never read letters which you may find addressed to others.
- Never fail, if a gentleman, of being civil and polite to ladies.
- Never call attention to the features or form of anyone present.
See full article and list at http://artofmanliness.com/2009/03/22/the-unclassified-laws-of-etiquette