I've been writing 'seriously' for about 17 years.
I think what the OP says is great advice. The list is especially useful for beginner writers, because it gives them a specific guide to follow.
I was taught the value of an introductory sentence and paragraph differently. I was told to simply "Be specific!" If you have a look at his dos, this simple phrase is put to use in all of them. The don'ts are the opposite: they're vague. I default to this be-specific phrase when I write.
Having said that, writing is such a tricky thing. All throughout my academic history, I've been taught the 'principles' of style only to have to unlearn half of them and adapt to a new 'standard'.
As a few people have written, context matters.
In the end (and in practice), you have to consider your audience, how much time you have to write (if it is your job, because there are hundreds of content mills), develop your own style (this itself is a trite/clichéd remark), but most importantly, have a reason to write that word or punctuation. This last concept is what I adhere to, which is why I only write short stories and poems. Novels are a completely different beast, though I am working on one slowly but surely.
I can read Shelley and Keats and love every expressed emotion. Most people will tell me, "But it's soooooo cheeeesy!" Damn right it is. So? What's your point? Context. Business writing is not creative writing is not poetry is not a short story is not a novel. Likewise, romanticism is not modernism is not postmodernism is not magical realism is not anything.
If you think about it, writing is a very depressing art form. It is one of few skills that has a low price tag in a society yet is valued by everyone. "Oh, he's a great writer! Found his book for cheap at a used bookstore! $1 for a classic!" The only writers that make a good chunk of change are the Stephanie Meyers or the sci-fi writers that pump out a book a month. Author mills. It is rumoured that it took Ezra Pound about six months to write a three-verse poem. Can people even tell the difference? Some say they can.
It's difficult to go in to an interview and act like I really know how to write. My use of grammar and style is poor. I edit a lot. Revise, revise, revise. It takes me an hour or more to write a short paragraph. It doesn't come naturally to me. The only thing I do better than others is spell correctly.
There is an ongoing joke that is repeated pseudosincerely: the worst thing you can do is take advice from a writer.
So what do I know.
PS: One of my favourite opening sentences comes from Camus's L'étranger:
Aujourd'hui, maman est morte. (Mother died today.)
This one is from Kafka's Der Prozess:
Jemand mußte Josef K. verleumdet haben, denn ohne daß er etwas Böses getan hätte, wurde er eines Morgens verhaftet. (Someone must have been telling lies about Josef K., he knew he had done nothing wrong but, one morning, he was arrested.)