In order for him to have success, he needs to be "on the grind". We have been hearing a lot about Fields having all the tools to be a great quarterback in this league.
Even his old head coach had kind words about Justin. During an appearance on the Rich Eisen Show, @KyleBrandt said that he talked to former Chicago Bears head coach Matt Nagy and Nagy told him that "Justin Fields has it. He has everything. He is the real deal. They got the right guy and he will be a star in this league."
Here is a video of Justin Fields working his butt out, even on vacation:
I also believe that Fields will take a huge leap in year 2. Historically, rookie quarterbacks almost always get a lot better in their second season.
Twenty quarterbacks saw their completion percentage rise by more than 1% in their second season, while eight had their completion rate drop by more than 1%. Nine improved their yards per attempt by more than 0.5 yards, and five saw that number drop by more than 0.5 yards.
On average, a second-year quarterback improved his completion rate by 2.10% and his yards-per-attempt by 0.22.