When is a comma unnecessary?

Many people use a comma where they would pause naturally in a sentence. While this simple trick often works, sometimes you end up adding a comma where it is not necessary. Adding unnecessary commas into a sentence can clutter it and make it less readable.
Here is some more specific guidance on when you don't need to use a comma:
Should you follow an introductory phrase with a comma?
When should you use a comma before a coordinating conjunction?
Do I need a comma after a subordinate clause?
Do I need a comma after a participle phrase?
To avoid using unnecessary commas, make sure that you are familiar with all the rules above.