William Safire's rules for writing as seen in the New York Times

Do not put statements in the negative form.
And don't start sentences with a conjunction.
If you reread your work, you will find on rereading that a great
deal of repetition can be avoided by rereading and editing.
Never use a long word when a diminutive one will do.
Unqualified superlatives are the worst of all.
If any word is improper at the end of a sentence, a linking verb is.
Avoid trendy locutions that sound flaky.
Never, ever use repetitive redundancies.
Also, avoid awkward or affected alliteration.
Last, but not least, avoid cliche's like the plague.

"They ought to make butt-flavored cat food." --Gallagher