Valtteri Bottas says that Williams must avoid making the kind of errors which cost him a haul of points during last weekend's Belgian Grand Prix.
Bottas qualified in third place at Spa-Francorchamps but Williams fitted one Prime tyre among three Option tyres when he came in for his first pit stop.
Bottas was handed a drive through penalty for the error, ending his chances of claiming a top five finish.
"Monza is a track that should really suit our car," he said in his post-race blog. "On the other hand, we need to analyse thoroughly why we weren't as competitive as expected in the Belgian Grand Prix and make sure the situation doesn't repeat itself in Italy.
"Of course a lot of work is going to go into understanding how the tyre mishap happened, because we need to fix the procedures and make sure such a problem never occurs again.
"We'll learn from it and I'm sure this will never be repeated. Without the drive through penalty I had to serve for the tyre mistake we would have finished the race in 5th place, as I was in front of that pack. Still, the pace was not good enough for a top three finish, which was our goal, so now is a time to learn and move on."
Bottas admits that Williams expected more from 2015 but is sure of improving across the remainder of the season.
"I think Williams is a great team to be with, and I'm confident they can be up there again in 2016," he said.
"There's no reason why Williams shouldn't be able to be fight with Ferrari and Red Bull. I do admit we expected more from this year's car, particularly in the first part of the season and if you compare it with 2014, then we had a few more podiums at this time of the year than we have now.
"Having said that we are still capable of improving and getting closer to Ferrari so I will be looking to secure more podiums in the second half of the season."