Odessa Again, by Dana Reinhardt

Odessa has lots of things that bother her.  She hates the fact that her father doesn't live with them anymore.  She hates that he's remarrying.  Her little brother drives her crazy because he is such a toad!  And she despises having to share a room with him.

So, she is pretty happy when she finally convinces her Mom to let her move in to the attic.  And it is there that she makes an amazing discovery:  by stomping her feet on the floor she can go back in time!  It's a very limited power:  the first time, she goes back 24 hours; the second time, 23 hours; and so on.  Very quickly, she figures out the powerful opportunity of the Do-Over.  At first, she uses it to benefit herself.  But, as time goes by, she comes to realize the value of (and limits to) improving the lives of others.

The story, in the end, is really about the importance of internal change, but the magical angle of time travel gives the story a bit of fun.  Odessa gets to grow up in fairly predictable ways (learning to appreciate her brother, reconciling with the changes going on in her family, etc.) but I really enjoyed its predictability.  I also really liked grownups in the story (always a big fan of adults who are people and not monoliths).  The drawings are cute too!