Sticks and stones may break your bones, but words can get you in a lot of trouble. 
Manners are always important. 
Smart is good. Lucky is better. Smart and lucky is the best of all. 
Sometimes the long way around is the best way home. 
Never let the truth interfere with a good story. 
(Neef’s Rules for Changelings)

[I’m covering two in one post here, since I just read both books back to back, and while each followed the archetype fairly well, and were enjoyable stories overall, neither impressed me very deeply.]

Changeling by Delia Sherman tells the story of (you guessed it) a human changeling living in the realm of fairy, within the boundaries of Central Park in New York City. Neef was taken from her human family long ago and remembers little of that life, other than her birth name. She longs to escape the confines of the park and her quiet life with her fairy godmother (a rat). This leads her to make some foolish decisions that result in the disfavor of the Green Lady who rules the park, and she can avoid disaster only by completing a difficult three-part quest. Her companion in these tasks is an unusual one – her own doppelganger, the fairy that took her place in the human world (but who doesn’t know what she is). While there are intermediary adversaries to defeat, the major foe is the Green Lady who holds Neef’s fate in her hands, although they don’t have a lot of interaction with each other. A fun story with some clever re-workings of fairytale tropes into a modern urban setting, but I was left feeling that Neef wasn’t terribly transformed by her adventures.

I admit that I first picked up The Search for WondLa by Tony DiTerlizzi simply because the heroine starts off underground, but then emerges above (in an unusual reversal of the occasional literal Girls Underground story).

Eva Nine has lived all of her 12 years in an underground home, raised by a robot called Muthr (an acronym). She is being prepared for life on the surface, but is impatient and dreams of running away. Before she can, however, her home is invaded and destroyed by the vicious creature Besteel, and she must suddenly survive all on her own. She finds that the world above is nothing like what she was taught (in fact, it doesn’t appear to be Earth at all). She must quickly acquire companions to help her escape from Besteel and hopefully find other humans like her (as usual, her primary companions are male, although she also reunites with Muthr when she makes the classic brief mid-journey return to her home). She also receives help from a strange seer – an example of the wisewoman/witch/granny role we often find in GU stories. She does manage to defeat Besteel through her own cunning, although the final showdown isn’t particularly climactic. But she does discover who she is and why she is there, in the end. And there is a wonderful nod to a classic Girls Underground story, which is also a common occurrence (most usually seen in Alice references in so many GU stories).