Leech has 6 maxims: tact, generosity, approval, modesty, agreement, and sympathy.
Tact is minimising imposition. For example: "Can I just interrupt you for a minute?"
Generosity is minimising self-belief. For example: "You relax and let me do the dishes".
Approval is giving approval to people and making them feel good about themselves. For example: "I heard you singing! I could tell you were enjoying yourself."
Modesty is limiting the self praise. For example: "I'm so stupid! I forgot to do [..]".
Agreement is to limit the disagreements.
Sympathy is to minimise antipathy. For example: "I'm so sorry to hear about your dog".