January's recommendation: Dealing with Dragons, by Patricia C. Wrede.
I didn't realize it until years later, but Cimorene was one of my role models while growing up. Not consciously, but still, if I were to be a princess, I'd want to be one like Cimorene.
She fits into the well-known archetype of the Misfit Princess. All her sisters are blonde; she has black hair. All her sisters are attractively small; she can look men in the eye. All her sisters behave properly; she takes fencing lessons, Latin lessons, juggling lessons, magic lessons, cooking lessons -- she keeps finding new and inappropriate lessons to take, and her royal father keeps on having to put a stop to them.
(Let's see. Fencing? Check. Latin? Check. Magic? Would be check if there'd been anybody to teach me. Cooking and juggling, I missed.)
Like all good Misfit Princesses, Cimorene has to escape the disagreeable fate of being married off to some prince she doesn't care for in the slightest. In Cimorene's case, she solves this problem by volunteering to be a dragon's princess, on the grounds that it's a perfectly respectable occupation for a princess. Of course, the usual modus operandi is that the dragon will carry off the princess while ravaging some place or another, but she finds one open-minded enough to take her in, and thus begins her employment with Kazul.
(If your copy of this book, like mine, has brainless cover copy about "a dangerously charming dragon," ignore it. Kazul is practical, straightforward, and female, none of which are implied by that phrase.)
This book reminds me in style of Diana Wynne Jones' novel Howl's Moving Castle. Both of them take place in the sort of fairy-tale fantasy kingdom that has a postmodern, ironic awareness of its own fairy-tale nature. Royalty worried about making good marriages for their daughters will hire evil fairies to come curse them at their christenings. The Enchanted Forest is full of all the sorts of weird creatures and questing princes you might expect. Navigating life in a world like this involves knowing how to exploit and subvert fairy-tale conventions to your own advantage. (Both books also have "In Which" chapter titles, which I have a peculiar fondness for.)
There are sequels to this book: Searching for Dragons, Calling on Dragons, and Talking to Dragons. They're absent from this recommendation not because I dislike them, but because I don't remember them; for whatever reason, I only ever owned the first one, and so it wormed its way into my heart far more deeply than any of the others. I believe the sequels are worth checking out, though.