According to John McIntyre, editor of the Baltimore Sun:
1. Fully exploded: Unless you are working for an uncommonly primitive and obtuse outfit, or your employer has slipped beyond ratiocination, you should not be observing any of these long-discredited superstitions:
No prepositions at the end of sentences.
No split infinitives.
No sentences that begin with the conjunctions and, but, and or.
No “split verbs” (no adverb between auxiliary and main verb).
No use of between with more than two persons or objects.
No beginning a sentence with because.
No use of decimate apart from “reducing by one-tenth.”
2. Not yet dead: Some operations cling to these pointless time-wasters:
Observing a distinction between since and because (reserving since for the temporal).
Observing a distinction between over and more than (reserving over for the spatial).
Observing a distinction between like and such as.
Observing a distinction between convince and persuade.
Refusing to use hopefully as a sentence adverb in the sense it is hoped that.
Refusing to use data as a singular noun.
Refusing to use none as a plural pronoun.
Refusing to use due to in the sense of because of.
Refusing to use while to mean although.
Insisting on who for people, that for animals and objects.
Insisting on loan exclusively as a noun.
Moving however from the beginning of a clause to the middle.
3. Room for judgment
Shunning passive voice: Bad for concealing responsibility. Good when it is not known who performed the action or the identity of the person(s) performing the action is of minor importance.
Maintaining a strict distinction between which and that. Often a good idea, but not always.
Insisting on whom as an object. Who increasingly serves as both subject and object except in the most formal cases.
Refusing to use they or their as a singular. Widespread in informal writing, and creeping into the formal