Look Back

The two stories are not clearly similar but if you love one you'll love the other because the two stories are clearly moving and well writen. The two stories had one of the best storytelling of all time and that makes them amazing.  

The question of what drives people to create manga/ anime is central in both works. In addition to this, both explore the multifaceted relationship between art and human interactions; how art can be, result from, cause and require communication between people. "Look Back" approaches this theme from a more individual and internal perspective, while "Shirobako" also looks at how it appears in the context of a wider net of interpersonal relationships. 

Both are stories of two mangaka that tracked largely similar journeys to success in their craft. "Bakuman" focuses on the technicals of manga drawing and serialization, "Look Back" focuses on the MC's bond. And both have scenes in the Shueisha office. 

Both are deeply emotional films that deal with the complex interpersonal relationship and personal development between two girls and the reasons they pursue their passions. Artistic expression serves as a central theme in both with Liz centerned around playing wind instruments and Look Back centering around drawing and manga. The relationship between the main characters in both films are also quite similar, with one being solitary and the other one being more outgoing.