The Elements of Style by William Strunk Jr. and E.B. White was first published in 1959 and over 10 million copies have been sold of this short book with rules of writing. Strunk was a professor of White's and self-published The Elements of Style in 1919. White forty years later expanded on Strunk's rules for the new book.
Form the possessive singular of nouns by adding 's - this is true even if the name ends in s, so "Charles's friend" is correct.
To form the contraction for "it is," write "it's."
In a series of three or more terms with a single conjunction, use a comma after each term except the last - this is a serial, or Oxford, comma.
Do not join independent clauses with a comma - if clauses are grammatically complete, they should be separated by either a semicolon or period.
Use the active voice. Put statements in positive form.
Use definite, specific, concrete language. Omit needless words. Be clear.
The number of the subject determines the number of the verb - don't combine singular and plural.
A participial phrase at the beginning of a sentence must refer to the grammatical subject.
Express coordinate ideas in similar form - this is the principle of parallel construction.
Place the emphatic words of a sentence at the end.
Avoid split infinitives - write "to inquire diligently" rather than "to diligently inquire."
Write with nouns and verbs, not with adjectives and adverbs (verbs that have "ly" added to the end).