One way is to think of some aspect about your book that might make an interesting story. For author Margot Raab, it was writing an opinion piece in the New York Times about how some people reacted with disdain when they learned her novel, which featured a teen main character but which she had not thought of as being a young adult book, was marketed as a YA. The piece ran just as the book came out in paperback.
And now Salon has an article by Rebecca Johnson about the difficulty of getting blurbs. It's a funny piece about how her editor suggested all kinds of famous folks she didn't know (Ann Patchett was who her editor lusted after).
Read the article here.
I'll have two books out next spring. Note to self: must think of some hook that relates to at least one of the books that can be turned into an article that ostensibly deals with a larger issue.