Arteta's team, who started the season with a 2-0 win over Wolverhampton Wanderers, travel to Villa on Saturday.
"They scored and we didn't, it's very simple," Arteta told reporters of the two defeats by Villa last season.
"In two games, even though we had an enormous amount of chances to do that, and that was one of the big differences, one of the details we have analysed. We have to do better tomorrow."
Arteta praised the job Emery has done at Villa, who beat West Ham United 2-1 in their opening game of the campaign.
"They are a really good side, really well coached," the Spaniard said. "They dominate every aspect of the game. When you give them space to run they are phenomenal and when they have to find space they are able to do that. Set pieces as well."
Arsenal have signed Italian defender Riccardo Calafiori and Arteta said there could be more new arrivals, although he remained tight-lipped on the potential recruitment of Mikel Merino from Real Sociedad.
"Anything can happen, both ways, and you have to be ready. Especially in the last week, you have to be alert and prepared because a lot of surprises can come for many different reasons," he added.
Asked if he was considering a move for Chelsea winger Raheem Sterling, Arteta said: "Raheem is someone I have really strong feelings about."
Arteta worked with Sterling when he was assistant coach at their former club Manchester City,
"My time with Raheem was exceptional. We built a really strong relationship together," he added.