How to master the fine art of flattery

Flattery, as Cicero would describe it, is the handmaid of the vices.

It's also been decried, according to historian Willis Goth Regier's "In Praise of Flattery," as "that filthy science," "the worst of vices," and the "prostitution of empty praise."

But flattery, historically and continually, serves a vital purpose - indeed, that's the difference between flattery and praise. Flattery is when praise seeks a reward, as Regier puts it. And it is considered by some "the most useful of all arts."

As we know, another person's ego can be your foe. In her book, "No One Understands You And What To Do About It," social psychologist Heidi Grant Halvorson explains that when someone feels threatened by your potential superiority and success, their egos can run amok and cause them to downplay your successes and even distance themselves from you.

Flattery, however, can be the great vanquisher - if used correctly.

The rules for flattery, or affirmation as Halvorson calls it, are threefold: