Leech's Six Maxims

Sympathy

Minimises antipathy and maximises sympathy, for example - 'I was sorry to hear you weren't well.'

Agreement

Minimises disagreement, for example - Perhaps we could agree to go at midday?'

Approbation

Minimises dispraise of the speaker, for example - 'Yes, I've seen your dress. It's so unusual.'

Modesty

Minimises praise of the speaker, for example - 'I'm so stupid. I didn't get that. Did you?'

Generosity

Minimises the benefit to the speaker and maximises the benefit to the listener, for example - 'You must come and have dinner with me.'

Tact

Minimises the cost to the listener and maximises the cost to the speaker, for example - 'Could I interrupt you for just one second?'