The Sweden attacker admits his teammates fall short with their standards in training day-to-day.
He told Sky Sports: "I think there are a couple of factors and one is here inside the training ground.
"To be a champion, you have to be a champion every day. You have to give everything every day.
"I feel we lack a little bit of discipline in terms of that consistency. That's what is missing.
"The quality is there, the football is there. But you have to do it every day.
"You can't be happy because you win a game, two games, three games. You have to win every game.
"I think these are the steps that we have to take. We have the football, but we have to get more disciplined. Maybe someone else has a different opinion, but that is mine."
On manager Ange Postecoglou, Kulusevski also said: "I think he's a very good man and a very good coach. I have learned a lot from him and I agree with his playing style.
"That's the way I want to play, very aggressive and always the same.
"But of course, we have to improve. What we are doing is not enough.
"We can see progress in our football but we want to win something this year and we have to see results too.
"It's a challenge for us together - the manager, the players, everyone at the club - to find a way that works. A lot of things we do are perfect.
"Offensively, we are very good. But we have to defend a little bit better, especially conceding some easy goals from crosses.
"We have to improve a lot on that, but I think we can fix that side of our game and I am enjoying working with the manager."