The Ghana midfielder joined the club in the summer after they activated his £45million release clause at Atletico Madrid on deadline day.
"Yes, it was a difficult moment to get used to how the team play and I think the injuries are part of the adaptation and now I feel good," Partey said ahead of Arsenal's Europa League last-16 first leg against Olympiacos.
"I'm doing all the necessary ways to be able to be more fit and to be be able to play more games."
Asked when fans could expect to see his best form, he added: "I think this is just the starting. I'm starting to get used to how my mates play and how the Premier League goes. With time everything will be good."