Hee—just came across a link (from the Malibu List Weblog) to Nick Lowe's article The Well-Tempered Plot Device, published in Ansible in 1986, about how to create bad plots. Lowe discusses the art of predictability; the use of plot devices; plot coupons (Lowe may have coined the term); redeeming plot vouchers; the Universal Plot Generator; and the use of deus ex machina.
Lowe was previously known to me only as the excellent film reviewer for Interzone; it turns out that he was a good enough writer even twenty years ago to make me enjoy the parts of this article I've had time to read so far even though he trashes Susan Cooper's Dark Is Rising series, Lord of the Rings, Star Wars, and Hitch-Hiker's Guide to the Galaxy.
He also trashes a bunch of other stuff: everything by Stephen Donaldson; the Shadow of the Torturer series; Leonard Nimoy's poetry; IASFM; Lionel Fanthorpe; A. E. van Vogt; Michael Moorcock; Lin Carter's The Black Star; and the comic-book concepts of red kryptonite and the Idol-Head of Diabolu. Among other things. So if you're likely to be upset by someone trashing any of those things, perhaps best to skip this article, or at least to brace yourself before reading it.