#3 Consistency
There is no doubt that the 24-year-old has been influential for Manchester United, but that seems to go away in the big games. Barring the EFL Cup final, he has failed to influence the big games. He had a torrid time against Chelsea in the FA cup quarter-final which could be linked to the sending off of Ander Herrera.
With Rooney and Carrick coming to the end of their careers at United and Smalling not assured of a place in the starting eleven, the former Juve star needs to step up and take the mantle of leadership.
He had a good relationship with Zlatan Ibrahimovic and should use that experience next season. With time on his side, and after gaining precious wisdom in his first season, he needs to improve next season.