Kubica made his return to F1 after nine years out of the sport, after a horrific rally-car crash caused severe injuries to his arm, and despite scoring Williams' only point of the season, has struggled to compete with his team-mate George Russell so far this campaign.
Williams has struggled againt this season, sparked by its inability to bring a car to the first few days of pre-season testing in Barcelona. The Polish driver is eager to get more consistency in the car he drives every weekend.
When asked by Motorsport.com to sum up the first half of the season, Kubica said: "It has been complicated. Overall, there are a few things that we have to get on top of apart from the performance of the car.
"I think once we fix them or we have more consistency it will be much easier, so hopefully the second part of the year we'll get on top of it and then at least we'll be able to have consistent performance every weekend, which will be much easier.
"You can always improve everywhere, but as I said, we have to have consistency. Once you have consistency in the car, it will also be much easier from the driver point of view to be consistent and to work on small details and this is in the end is what it comes down to in F1."