The Croatian international made the move to the Bernabeu from Tottenham Hotspur last August after lengthy negotiations between the clubs.
The prolonged transfer talk meant that the 27-year-old was unable to take full part in Real's pre-season, something that Modric insists has prevented him from discovering his best form in Spain.
"Everyone says the Spanish league is a very technical league and I agree, but it is also very demanding on a physical level," said Modric. "It was a very demanding summer. I didn't have a pre-season and that has had an influence.
"I didn't know if I would be going to Real or not, which affected things and the whole team hasn't played like it did last season so this has also complicated things for me.
"But the squad have had a lot of patience with me, they have supported me and I have confidence in my ability. All I have to do is keep working hard every day to improve and things will get better."