A comma splice is when a comma separates two independent clauses without a coordinating conjunction (or semicolon).
When you use “but” to join two independent clauses (each of which can stand alone as a sentence), a comma should be placed before “but”.
Use commas before “and” when joining two independent clauses to form a compound sentence. Sometimes, a comma is used after ‘and’ in a series or list.
Read the GrammarFlex guide on the 8 main rules of comma use in English grammar and writing.
What’s an Oxford comma, anyway? When and where is an Oxford comma used in sentences, and when is it best to omit the Oxford comma altogether?