Shujinkou Nikki  

主人恋日記, Diary of a Female Lead: Shujinkou Nikki

Aoi Tsujimura doesn't see herself as a main character in the traditional sense. She is introverted and insecure, in contrast to her athletic older brother Itsuki and her mother, who is a famous shoujo mangaka. While she doesn't need to be the heroine, Aoi desires a true friend. However, Itsuki disagrees with her, and when he brings home Sena Mizusawa, their classmate who is effortlessly cool, they devise a plan to teach Aoi about love using shoujo manga as their guide. Can this side character transform into a remarkable female lead through falling in love with the ideal guy?