This document provides guidance on avoiding common punctuation errors such as run-on sentences, comma splices, and fragments. It explains what commas, periods, and semicolons signify and how to identify run-on sentences and comma splices. Various methods are presented for correcting punctuation errors, such as using periods to separate sentences, semicolons followed by transitional words, commas with FANBOYS conjunctions, and joining sentences with subordinating conjunctions. Practice examples demonstrate how to identify and fix errors involving run-on sentences and comma splices. The main cause of sentence errors is confusing different joining words and their required punctuation.