The forward joined Ronald Koeman’s men from Charlton in January, and has since being a regular face in the Toffees’ squad, netting a goal in just five appearances.
Lookman has enjoyed a meteoric rise at Goodsion Park, and the Wales international claims the Nigerian has brought unpredictability to the team’s attacking play.
''Ademola has really good potential but he is also ready to play in the first team already,” Williams told Everton website.
“He has a lot to learn, everyone does at that age, but he has made an impact already and given us something different that we didn’t have.
“He is a bit of a wild card. Teams don’t know him so well. He is a nice lad as well and has got his head down, worked hard every day and is listening.”
Everton are seventh on the English topflight log with 41 points, and they face relegation threatened Sunderland on Saturday.