Grammarly
Grammarly Blog: Comma Between Two Nouns in a Compound Subject or Object
This page focuses on the misuse of a comma by placing one between the two nouns in a compound subject or object. It provides examples of its misuse and explains why it is not correct.
Grammarly
Grammarly Blog: Comma With Subjects and Verbs
This page focuses on the misuse of a comma when it is used to separate the subject of the sentence from the verb. It provides examples of such sentences and one exception to the rule.