 If you liked Piano no Mori (TV) |  ...then you might like Given |
Both series deal with music, and a character's urge to better their abilities in order to honour someone important to them. Both main characters go from knowing nothing about their instruments to being ble to play them well across the series. The young male characters are easy for audience members to find themselves reflected in.
both are shounen stories based around music. but they are different in a way that given is shounen ai and focuses on a relationship between two boys, and piano no mori isn't (offically) romance but also focuses on the relationship and rivalry around two pianists (basically a non-canon ship). if you liked one of these, you're probably going to like the other.