Excessive use of commas can spoil an otherwise fine sentence.

Around restrictive elements

Do not use commas to set off restrictive elements—elements that limit, or define, the meaning of the words they modify or refer to (39c).

Between subjects and verbs, verbs and objects or complements, and prepositions and objects

Do not use a comma between a subject and its verb, a verb and its object or complement, or a preposition and its object. This rule holds true even if the subject, object, or complement is a long phrase or clause.

In compound constructions

In compound constructions (other than compound sentences—see 39b), do not use a comma before or after a coordinating conjunction that joins the two parts.

The and here joins parts of a compound subject, which should not be separated by a comma.

The and here joins parts of a compound predicate, which should not be separated by a comma.

Before the first or after the last item in a series