Basic rules of punctuation include the need for punctuation to be parallel, the use of a dash as a strong comma, and the use of apostrophes to show possession or indicate omission. Also, writers use semicolons to join two related independent clauses of equal importance.
Parallelism in punctuation refers to the use of a single mark more than once when used in a series. For instance, a list that is separated by commas must remain separated entirely by commas. It is incorrect to place a semicolon or other punctuation mark in the same list. Parallelism also applies to grammatical structures such as quotation marks and dashes, which need to be written before and after the phrases they contain.
Use dashes like commas, but for greater emphasis. Dashes draw attention to the words they preface, making them ideal for directing a reader's focus to the last item of a list.
An apostrophe indicates ownership of a noun when combined with the letter "s" in the owner's name. While singular possessive nouns end with "s," a plural possessive noun that already ends in the letter "s" needs only an apostrophe to indicate ownership.
Writers use semicolons to separate two independent clauses that could be two sentences but are related enough and of equal enough importance to be connected.