Quote:
Originally Posted by VydorScope
Yes, and no.
What you want to do is get a good book like The Chicago Manual of Style and do your best to follow the directions. Then get a good editor to look it over when you are done. There are many comma rules that are hard and fast, and some that are iffy, and others that are out right argued to death. What matters most is that you are consistent with the subjective ones, and hit the objective ones as solidly as you can.

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VydorScope provides good advice. Additionally, I recommend reading Chapter 5 of SparkNotes' handy ACT Test Prep Guide;
this link accesses the punctuation lesson about commas.