Arteta was speaking yesterday as he welcomed new sporting director Andrea Berta to the club.
He said: "The way we planned the five first summers (since I took charge), they were going to be very big and they were going to have different objectives because the turnaround of players and the objective of those windows was different.
"Now we want to increase the depth of the squad, but as well we want to increase the quality and the skills that we need to go to the next step. It's going to be a big one and we are very excited about it."
On Berta, he said: "What I'm very confident about is how he's going to make everybody better. Because of the way he is, because of the personality he has, the way he talks and how passionate he is. And that's what we need. New blood with people that are ambitious."