The rule of three

This is an old trick of the trade that doesn't get mentioned a lot nowadays （it's called tricolon in classical rhetoric）, but that crops up all the time in good writing. The idea is simple: lists of all kinds （of things, qualities, actions, reasons, examples, etc.） tend to come across most powerfully when they contain three items. Of course that doesn't mean you should manipulate your material to make it fit. Sometimes you'll want to put two, four, or more items in a list. But when you've got flexibility in what to say, keep the rule of three in mind:

　　Coriolanus doesn't hide his contempt for the commoners, he doesn't flatter them, he doesn't try to soften his image.

　　A generation ago most scholars believed that an overarching worldview—conservative, deeply Christian and essentially medieval in its commitment to order and hierarchy—shaped the concerns and defined the intellectual limits of Shakespeare and other Elizabethan dramatists.

　　The third term is often slightly larger in its focus than the first two, enfolding them to make a more general point.