This will start out boring for non-punctuation-lovers, but then I'll quote Robert Frost, which is always a great benefit to society. So slog through the boring part to get to the poetry and my explanation of how Frost shows how important it is to "know the rules, then break them."
Here's a minor comma fix, and it's more "discretionary than obligatory:" The Oxford comma.
For some reason, the final comma in a series (before the "and") is called the Oxford comma, but it's also called the "serial comma". The rule is, when you have a series of three or more items in a row, with "and" before the last one, you put a comma before the "and" so that there's a comma after each item. So: The US flag is red, white, and blue.
This is done differently in journalism, where they used to have to save space and ink and so eliminated as many comma rules as they could. J So you'll see the "and" without a comma before in magazine and newspapers and often on news websites too.
Academic writing, however, follows the rules of book publishing, and the "Oxford comma" is the convention there. Just a minor change, and as I said, this is a rule in academic and book writing, so you'll often see series without that comma in the popular press.
More about the "Oxford comma"
What About Robert Frost, You Ask?
The great American poet Robert Frost surely knew the rules. No one made better use of the conventions of the language and grammar than he did in creating his deceptively simple and lovely poems. He's a great example of how understanding the convention (and how the reader would conventionally read something) in order to subvert it for a greater or deeper meaning-- punctuation becomes subtext.
Now as I said above, the general rule followed by book editors and publishers is that when there is a series of three or more like items (like three adjectives), you place a comma before the "and" or the last item in the series, indicating that these are all basically similar and yet separate from each other.
So with Frost's poem in manuscript, the book editor (or, as the Frost myth goes, the typesetter of the book, cleaning up after the editor
) saw this line with this series:
The woods are lovely, dark and deep
Well, of course the punctilious editor/typesetter made haste to add that Oxford comma-- the RULE.
And usually, that would have been exactly correct.
However, again according to myth, Frost saw the proofs and quickly "stetted" or insisted that the original be maintained.
Why? Was Frost being stupid? Did he not know the rule?
He knew the rule. He knew what effect abiding by the rule would create for the reader. And he knew he wanted another effect, one that could be achieved by subverting the rule.
Let's look at the two meanings-- comma in or comma out.
Here's the entire stanza. This is the final verse of that achingly beautiful poem, "Stopping by Woods on a Snowy Evening". (You can read the whole poem, and you really should, here at the Poetry Foundation.)