The France winger faces former club Wigan Athletic tomorrow.
He said: "There's definitely more to come from me. It's only been a month and a half since I came here.
"I think we are missing something in the final third.
"Perhaps we are too direct but hopefully a goal or assist will help me to feel more confident in the team.
"I focus on being on top of my game and don't worry about the transfer fee. I am not concerned with the money that was paid. I just try and win football matches.
"I know I just have to step up a gear. I just want to work hard whether I have a good or a bad day."