I would suggest a literary agency (if one will agree to take you) as your best option. A literary agent is the gatekeeper between the great unwashed masses of wannabe published authors, and the publishing houses. You could learn a lot from an agent about what constitutes a good book, and what makes a good book good enough to stand out from the hundreds of queries they receive a week, for them to consider representing it. You will also learn invaluable lessons about how to craft a query letter and synopsis, and see how agents network with those in the publishing biz.
If you want to try working for a literary agent, you will have to show discerning taste, be able to tell good writing from bad, you will have to love books, and you will have to be able to converse intelligently about the current literary market (books you like, genres and authors etc), and you should research a the publishing industry. Try some blogs like Miss Snark and Nathan Bransford.
While shadowing an author may seem like a good idea, as another answerer mentioned no author worth their salt wants anyone else hanging around bothering them. Besides, if you think about it, novelling isn't a spectator sport. A novelist only wants to focus on writing, not on teaching a writing class.
As someone else mentioned, a newspaper is a also a good (and possibly more achievable) option.