The Dirt Diary by Anna Staniszewski

Rachel is already having trouble with the popular kids at school when her mother starts a house cleaning business to help them get by after Rachel's father leaves.  Now Rachel is spending her weekends cleaning the houses of the same kids who already make fun of her!  But Rachel starts to pick up a lot of interesting information cleaning the houses of the popular.  Maybe she can use it to her advantage...

So I was just saying how I can't think of any books with biracial characters, and the very next book I read involves a biracial character.  The book itself has nothing to do with Rachel being biracial, but it does mention how Rachel looks more like her Asian father, and some people hadn't realized she and her mother were related.

Rachel's father leaving hit her hard.  She was much closer with her father than her mother.  Even though her dad's the one who left them, Rachel still feels like he understands her better.  She's sure that if she can just get out to Florida (she and her mom live in New England) where her dad is living, she can convince him to come back.  But Rachel's mother won't let her go.  Rachel took money out of her college fund to buy a ticket, and now she has two weeks to get the money back before her mother finds outs.  That's why she's stuck helping clean houses.  And that's why she takes the offer to spy on a mean, popular girl whose house she cleans.

Rachel thinks of herself as a loser.  She's incredibly quiet and shy.  She can't speak up or defend herself when others tease her.  She has a hopeless crush on a popular boy she's never spoken to.  The mean girls, lead by queen bee Briana makes Rachel's life terrible, playing mean pranks on her.  Rachel takes out her anger and frustration by baking.  She loves to bake.  It's what she wants to do with her life, but her mother doesn't think it's a practical career.  Rachel is determined to win this year's bake sale, not just because of the cash prize, but to prove she's good enough.

Rachel struggles with fights with friends, spying on people, which she knows is wrong, crushes on boys, and most of all, the absence of her father.  Rachel does eventually come to see that it's her mother that's there for her, even if she doesn't understand Rachel as well as her father did.  Her mom is the one who stayed, who always tried to fix things.  They are on the same side a team.

Good middle school read, dealing with all the important issues of finding yourself and learning who your true friends are.

The Dirt Diary comes out January 7, 2014.