On-loan at Aston Villa from Manchester United, Sancho has struggled to make an impact under manager Unai Emery so far this season.
Terzic worked with Sancho at Dortmund and told Sky Sports: “First of all, Jadon is special. Why? Because if the game is in the 75th minute and 0-0, you want him to get on the ball because you know that he is going to make something special happen.
“If you are expecting something special then you also have to treat him in a special way and I think the most important thing for Jadon... if you compare him to Jude (Bellingham), you need to keep Jude hungry, and Jadon you need to keep him smiling.
“If you talk to the joy of the kid inside of Jadon then you're going to get the best out of him. If he's smiling he's going to make a difference.
“It's a mix of talking to the professional in Jadon, but also to the kid in Jadon.”