I recently discovered "George Washington's Rules of Civility" on the internet. There are 110 maxims that helped shape and guide America's first President. I have read them all and I am including some of them, without comment, here. (Some grammar items have been modernized.)
When in company, put not your hands to any part of the body not usually discovered.
Shift not yourself in the sight of others, nor gnaw your nails.
In writing or speaking, give to every person his due title according to his degree and the custom of the place.
In your apparel be modest and endeavor to accommodate nature, rather than to procure admiration; keep to the fashion of your equals, such as civil and orderly with respect to time and places.
Associate yourself with men of good quality if you esteem your own reputation; for 'tis better to be alone than in bad company.
Think before you speak, pronouce not imperfectly, nor bring out yours words to hastily, but orderly and distinctly.
Undertake not what you cannot perform but be careful to keep your promise.
Drink not too leisurely nor yet too hastily. Before and after drinking wipe your lips. Breathe not then or ever with too great a noise, for it is uncivil.
Rinse not your mouth in the presence of others.
Labor to keep alive in your breast that little spark of celestial fire called conscience.