The 19-year old Belgian striker is on a season-long loan with the Baggies from Chelsea and after a solid start to the 2012/13 Premier League campaign, Clarke feels that the talented player can live up to his enormous potential.
"I've been delighted with him so far. He's made a good contribution to a really good team start to the season," said Clarke.
"He's also got a lot to learn.
"I think if you take the attributes he's got and what he's shown so far he has the potential to be a really good player.
"We will try to cause the Fulham defence as much (trouble) as West Ham did but we will do it our way.
"It's about how well you are improving as a player and that was the most important thing for Romelu.
"I promised we'd improve him. Hopefully, I can live up to that promise."