Comma before "so":
* Conjunctive adverb: When "so" is used as a conjunctive adverb (like "therefore," "however," or "thus"), it's usually preceded by a comma. This creates a pause and emphasizes the connection between the two parts of the sentence.
* Example: "The weather was bad, so we decided to stay home."
* Introductory phrase: If "so" begins an introductory phrase (like "So, let's continue"), it is typically followed by a comma.
* Example: "So, let's continue our discussion."
Comma after "so":
* Not a conjunctive adverb: When "so" is not acting as a conjunctive adverb, it generally doesn't require a comma after it.
* Example: "I was so tired, I went to bed early." (Here, "so" is part of the adjective phrase "so tired.")
Important Note: Sometimes, even when "so" is acting as a conjunctive adverb, you might not need a comma if the sentence is short and the connection between the clauses is very clear.
* Example: "I was hungry so I ate." (The comma is optional here, but the sentence is clear without it.)
Ultimately, the best way to determine if you need a comma is to read the sentence out loud and see if it makes sense with a pause.