END MARKS
Memorize these basic rules:

• Rule 1: Use periods (.) at the end of statements and commands.
• Rule 2: Use question marks (?) at the end of questions.
• Rule 3: Use exclamation marks (!) at the end of exclamations.  NOTE: Exclamations do not need to be written as complete sentences.

• Rule 1: Place commas before coordinating conjunctions (a.k.a. FANBOYS) that join two independent clauses together.  (Cross reference notes from September 10.)
• Rule 2: Place commas between items in a series.

(A variation on this rule is to place a comma between coordinate adjectives that precede a noun, but not between cumulative adjectives.)
• Rule 3: Place commas after introductory words, phrases, and dependent clauses.  (Cross reference notes from September 29 and September 5.)
• Rule 4: Place commas around non-essential words, phrases, and dependent clauses that interrupt a sentence.  (Cross reference notes from September 21 and again from September 19.)