The thing about writing is that, as soon as you try to impose a set of rules on it, it starts to go wonky. This is because you don’t write in a set of rules, you write for sense and rhythm. With punctuation you just need to know what your options are, and then think about the sound and sense you want to get across. Take this sentence, for instance:
Many a day I have sat and looked at a sentence and wondered to myself where does the comma go.
It doesn’t make sense. At the very least it needs a colon and a question mark.
Many a day I have sat and looked at a sentence and wondered to myself: where does the comma go?
I reckon some inverted commas would go well in there. Give it an ‘out loud’ kind of feel.
Many a day I have sat and looked at a sentence and wondered to myself: “Where does the comma go?”
Hang on a sec. It’s got a good cadence to it, but it’s getting a bit overblown. How about just using some commas in there instead? How would that go?
Many a day, I have sat and looked at a sentence, and wondered to myself, where does the comma go?
I’m getting close to what I wanted. But perhaps that last comma is one too many. Last try.
Many a day, I have sat and looked at a sentence, and wondered to myself – where does the comma go?
Perfect. 🙂 Or maybe not. Maybe I should just take all the commas out and start again? This is basically what I sit and do all day as a writer. Move commas around. Pretend I’m going to allow myself an exclamation mark and then scrub it out. I don’t wonder about whether I’m getting the rule right. I wonder about whether it makes sense and has the rhythm I was after. So if anyone ever tells you that you can’t put a comma before ‘and’, then don’t believe them. Because you can put the damn things wherever you like*.
* unless you’re writing a list, or doing your Key Stage 2 SATs