Which punctuation mark to use. Once decided, it will help if you make a distinction between the two main kinds of punctuation marks. It is within the sentence structure that you consider these decisions.
Periods identify word groupings that can stand alone.
While Frank went to the store. Too few periods will result in or comma splices, Frank went to the store Josh studied. Frank went to the store, Josh studied. To avoid this kind of punctuation problem, at least in such straightforward cases, you simply have to be able to recognize coordinate and subordinate clauses. Recognizing subjects and predicates will help you avoid the error of wrongly separating these fundamental sentence parts.