How To Get What You Want by Peony Pinker — Jenny Alexander

Peony wants a lot of things. She wants a dog, she wants her dad to stop being an agony aunt, and she really wants to get rid of her sister's horrible best friend Bianca. Then Mr Kaminski next door tells her the secret of how to get what you want, and Peony decides it's time to put a stop to Bianca at last. But can she get what she wants?