Appiah was in Goteborg to watch the 20-year-old play for BK Hacken in a 4-3 defeat to Danish Superliga side Lyngby in an international club friendly on Monday evening.
The 54-year-old is touring two Scandinavian countries to scout for players eligible to play for Ghana.
Waris-who tops the scorers' chat in the Swedish Allsvenskan with 12 goals from 12 games-, says he is motivated by the Appiah's visit.
"I think he was happy with me because I did some great work on the pitch.
"He advised me on somethings I need to add to my game. He said he was happy with my performance."
Waris is expected to be handed a place in the Ghana's squad for the next international assignment.