1. Coordinating Conjunctions (FANBOYS):
* For, And, Nor, But, Or, Yet, So
* Use a comma BEFORE the coordinating conjunction when it joins two independent clauses (complete sentences).
* Example: We went to the park, and we played frisbee.
* Do NOT use a comma if the connective joins two words, phrases, or dependent clauses.
* Example: I love both pizza and ice cream.
2. Subordinating Conjunctions:
* Because, since, although, while, unless, if, when, etc.
* Use a comma AFTER the subordinating conjunction IF it comes at the beginning of a sentence.
* Example: Because it was raining, we stayed inside.
* Do NOT use a comma if the subordinating conjunction comes in the middle of the sentence.
* Example: We stayed inside because it was raining.
3. Conjunctive Adverbs:
* However, therefore, moreover, nevertheless, consequently, etc.
* Use a semicolon (;) BEFORE the conjunctive adverb and a comma AFTER it when it joins two independent clauses.
* Example: We had planned to go to the beach; however, it started to rain.
* Use a comma AFTER the conjunctive adverb when it joins two phrases or dependent clauses.
* Example: He was tired, therefore, he went to bed early.
Remember: Pay close attention to the structure of your sentence and the type of connective you are using.
If you are unsure, it's always best to err on the side of caution and use a comma.