In a list of three or more elements, add a comma after each element except the last.

Use a comma before a coordinating conjunction or a correlative conjunction to separate two independent clauses.

When two independent clauses are joined by a correlative conjunction, use a comma to separate them.

Frequently, no comma is necessary when using "rather" or "rather...than". However, there are particular sentence structures where commas are required.

When using the conjunction "not only...but also" (or "not only...but"), place a comma before "but" if the second part of the sentence is an independent clause (that is, if it expresses a complete thought and has a subject and a verb).

Since "neither" (or the pair "neither/nor") connects two ideas, subjects, or objects together, you should not use a comma to separate them.

Generally, you should not use a comma before or after "either" when acting as a conjunction, determiner, or pronoun. However, when acting as an adverb (to agree with a negative statement), the use of comma before "either" is optional.

As a general rule, do not add a comma before or after "both" in a sentence. However, you can use a comma after "both" to serve a grammatical function, such as adding a non-restrictive expression or starting a sentence with a dependent clause.

Use a comma before a coordinating conjunction to separate two independent clauses. Often a comma is unnecessary when the coordinating conjunction is not followed by an independent clause.