McLaren say 2019 is an "important year" as they seek a route back to competitiveness following one of the worst seasons in their history.
Chief executive Zak Brown said: "There is a lot of cautious optimism but we don't want to get ahead of ourselves.
"We've done that before and we're not going to make the same mistake twice."
McLaren expected to challenge for podiums in 2018 but instead found themselves with the second worst car on the grid for much of the season.
That led to a major restructuring programme, the departure of several senior figures and the arrival of a number of new ones as the team sought to resolve the problems that had led to producing such an uncompetitive car.
McLaren have historically been one of the strongest teams in Formula 1, winning 12 drivers' championships and eight constructors' championships between 1974 and 2008. However, their last race win was in 2012.
"Development is going well. We're kind of on-track with what we are wanting to achieve," said Brown.
"We have no idea where the competition is other than speculation. I don't think we will know until we get to [pre-season testing in February in] Barcelona but we are pleased with the progress we have made.
"We have done things differently. Everyone is working well together so it feels like a more quiet confidence but we're on our toes. we know this is an important year for us to show progress and that comes with some exciting nervous energy.
"We know we are not going to get there overnight. It is going to feel good before it looks good, because there is a lag in what we do today doesn't hit the track tomorrow."
Will the Renault engine improve?
Brown said engine partner Renault, which lagged some way behind the standard-setting power-units of Mercedes and Ferrari, was optimistic it had improved.
"They are telling us that they are very pleased with their winter progress," he said. "That they have found a lot of kilowatts, and think that they will be in the ballpark.
"I don't think it's appropriate for me to quote the numbers they have given us but they feel they are going to be very competitive next year."
What about drivers now Alonso has gone?
McLaren have an entirely new driver line-up next year following the retirement of two-time world champion Fernando Alonso, who scored 80% of their points in 2018, and their decision not to continue with Belgian Stoffel Vandoorne.
Spaniard Carlos Sainz has been signed from Renault and his team-mate will be British novice Lando Norris, who was McLaren's reserve driver in 2018 and in whom the team have great hopes.
Brown said he had been impressed with a "very aggressive" Sainz so far.
"He is very engaged with the engineering team," added Brown.
"He wants to know. He spends time on the phone, with me, with the engineers. He's had a lot of off-season conversations with Fernando so he's very engaged and I think he's very excited and he's fully up for joining us on our road to recovery.
"He is under no illusions that next year is going to be a tough year."
Will Alonso be involved at all?
Alonso maintains a relationship with McLaren, who are setting up a team for him to have a second assault on the Indianapolis 500 in 2019.
There is a tentative plan for the 37-year-old to test the new McLaren at some point but nothing definitive yet.
"He is for sure going to watch our progress with interest because he is still part of the family," said Brown. "We have spoken about testing and it is something were are going to talk about further over the winter.
"We need to look at our entire programme. Certainly having his experience in the car would be a great thing but we need to make sure our two new drivers get sufficient time because they are going to be our race drivers next year, so it is an ongoing conversation."