After being suspended in March due to the coronavirus pandemic, the LaLiga campaign is set to get back underway on June 11.
Madrid are two points behind leaders and rivals Barcelona with 11 matches remaining this season.
Kroos, whose side host Eibar in their first game back, said whoever adapted to playing behind closed doors would be successful.
"We are training hard to get to the first game in the best possible shape. We can't do any more, this situation is the same for everyone," he told Real Madrid TV.
"We have to train well on our fitness, on our feeling with the ball and on how we have to play as a group, we are training for the 11 matches coming up.
"It's the first time we have to play matches without the fans, let's see how it is, and the team that adapts better to this situation is the one that will win."
Madrid had lost three of their five matches in all competitions before the season was stopped due to COVID-19.
Kroos said returning to working with the ball in training had been important ahead of play resuming.
"It's much better to train with the group, you have to play matches in training. Now it seems to be more normal and we like it more," the German said.
"The weeks we've been at home we haven't touched the ball much. We could work on the physical side of things at home, but not on the ball and even less so with the group.
"The most important thing is to touch the ball a lot."