Theresa May has admitted she failed to get across her vision for Britain's future in last June's general election.
The Prime Minister, who saw her Commons majority wiped out after calling a snap poll, said the Conservative campaign had been too centralised and needed to look again at the way it used social media.
In an interview with the former Tory leader Lord Howard for Parliament's The House magazine, she said they also needed to make again the argument for free markets among a generation of younger voters.
Speaking ahead of the Conservative Party conference in Manchester, Mrs May - who has been widely criticised for her performance on the campaign trail - acknowledged her central message of a "country that works for everyone" had not got through to voters.
"When I came into Downing Street I stood on the steps and I set out my platform for the future. That didn't come through in the election - the sense of a country that works for everyone, and the way that I wanted to take that forward. I think that was one issue," she said.
She said the Conservative campaign should have been less centralised with greater scope for activists on the ground to make their own decisions.
"You obviously need to have a central focus in the campaign. But I think that an awful lot of people out there in the party worked hard on the ground, and there is a feeling that there wasn't the ability to do what they wanted to do," she said.
Mrs May acknowledged the Conservatives failed to win a majority among any age group under 40 and said they had to remake the arguments for free markets and sound management of the economy among younger voters.
"Sadly we do see that that message has been lost. I think in a sense we thought those arguments were done and dusted. That everybody understood it. That we didn't have to go back to them," she said.
"We've got to make that case all over again, because there is a generation who have grown up in a different environment and perhaps haven't seen the problems that can occur when you don't believe in free markets and sound management of the economy."
Pressed by Lord Howard that the Tories had been "out-campaigned" on social media, Mrs May said the party needed to look seriously at the way it had been used by rivals to generate "negative atmospheres" around particular politicians or political interviewers.
"I think that, perhaps as a party or as a Government, we've seen social media as a means of trying to disseminate a message. But others are using it in a much more varied way," she said.
"They're using it to create an atmosphere around what is being said, around interviews, around events, which leads people to question them.
"It creates an atmosphere of disbelief in people's minds, rather than an atmosphere where people are actively thinking about the arguments that are being put forward."