In Hamlet, some of the main rules from Polonius's farewell speech to his son Laertes are the following:
Polonius advises Laertes to refrain from sharing his thoughts with others and not to be passionate. Polonius also tells his son to be kind to people, to keep in touch with his old friends but to be moderate when adopting new friends. For Polonius, it was more important to listen than talk.
Besides, Laertes was talked to wear elegant outfits but not to be arrogant, to refrain from borrowing or granting money, and to be sincere to himself beyond all circumstances.