Brett Kelly's Evernote Essentials ebook has become the quintessential resource for any Evernote user who wants to get the most out of the service. Today, he has released v3.0 of the book, and it's chock-full of new content. In fact, it's nearly double the size of the last edition (now 159 pages), and even the previous content has been rewritten to reflect Evernote's newer features.
Even if you use Evernote all the time, I'll bet this book can still teach you a few tricks. Do yourself a favor and pick up a copy.