I don’t care who you are — blogger, freelance journalist, ghost writer, ad copywriter — if you are writing on the web then you need to absorb copywriting mechanics.
There are two ways to get to that point: learning and practicing. I can’t help you with the practicing part. You just simply need to write … and keep on writing. But I can help you with the education part.
What follows are the nine books from the legends of direct response. Two are more recent than the others (and Influence is not technically direct response). These are the books I would demand you read if teaching a ground-level course on writing for the web since so many principles of direct response copywriting obey the unbreakable law of the web.