Element 1: Blossoms (preferably cherry, but anything red or pink will do)
Element 2: Fans (preferably held so as to partly obscure a woman's face (or genitals), and if you can get blossoms on the fan, you get bonus points)
Element 3: Dragons (for use only on crime novels, or other exciting tales)
Element 4: Female Necks (preferably that of a geisha, but any female neck will do in a pinch)
You'll notice that only women are allowed on the cover of Chinese and Japanese literature. Ideally, they will be either expressionless (some might say demure or inscrutable), or at most vaguely melancholy.
For more on this trend, see this article from Hyphen Magazine, which features a brief interview with ace designer Henry Sene Yee. It was that article which also drew my attention to two covers featured above, those for On a Bed of Rice and The Street of a Thousand Blossoms.
(To be fair, I ought to note that several of these covers are actually very nice--it's just that they lose rather a lot of their impact because of the familiarity of the elements used.)