Don't add final s to afterward, toward, upward, downward, backward, earthward, etc.
Don't use "signed" before the signature of a letter or document; run signature in caps.
Don't begin a sentence or paragraph with figures; insert a word before the figures or spell out.
Don't use commas in dates or in figures which denote the number of a thing, as A. D. 1908, 2324 State street, Policy 33815; in other cases use the comma, as $5,289; 1,236,400 people.
Don't forget that the following are singular and require singular verbs: sums of money, as $23 was invested; United States; anybody, everybody, somebody, neither, either, none; whereabouts, as "His whereabouts is known."
Don't forget that things OCCUR by chance or accident, and that things TAKE PLACE by arrangement.
Don't "sustain" broken legs and other injuries.
Don't "administer" punishment.
Don't confound "audiences," "spectators," and casual "witnesses."
Don't say "party" for "person."