One thing that’s true about happiness — there are very few new truths out there.
The greatest minds in history have turned their attention to the subject, so while it’s often challenging to put that wisdom into actual practice, it’s pretty clear what kinds of actions are likely to yield a happier life.
Likewise, “tips lists” have been around for a long time. I get a big kick out of uncovering tips lists from the past: Sydney Smith’s tips for cheering yourself up from 1820, Francis Bacon’s tips for how to be happy from 1625, Lord Chesterfield’s tips for pleasing in society from 1774.
In De Civilitate Morum Puerilium Libellus: A Handbook on Good Manners for Children, Erasmus gave seven tips about how to behave yourself around other people. He wrote this list around 1500 A.D., and his advice has a long shelf life.