If you followed the conversation on the previous blogs on the word so, you know that a conjunctive adverb needs a period of semicolon in front of it when it starts a new sentence. And that is the key to look for: Is it in front of a complete sentence?
...Ron had had three speeding tickets; yet he was not deterred from driving fast.
...Hanson was on the committee; still he didn't seem to know what was going on.
When there is not a complete sentence after the conjunction, use only a comma.
...Ron had had three speeding tickets, yet was not deterred from driving fast.
...Hanson was on the committee, still didn't seem to know what was going on.
Happy punctuating!
Margie