Today, because I'm exhausted of novellas, I'm just going to post a link to a blog that I subscribe to. Lit agent Nathan Bransford.
It's well worth checking out. If you're looking for expertise on how to approach a lit agent, how to write a query letter, how to mow your lawn in jockey shorts. Well, okay, not that last one. Some things you just got to try on your own.
Anyway, good stuff to be found here.