In a speech launching the manifesto at Battersea Power Station in south London, Mr Cameron said it was the "the biggest call to arms this country has seen in a generation".
He said no government could solve all problems on its own and he wanted "everyone to get involved", adding government should be the "partner of the big society, not its boss".
BBC political editor Nick Robinson said there was a "difference in philosophy" between the Conservatives and Labour, with the Tories saying "government needs to be pushed along" by the general public, while Labour was pledging that "government can be on your side".
Community 'right to bid' to run post offices
Eliminate bulk of structural deficit over a parliament
Cut £6bn 'wasteful' spending in 2010/11
Cut number of MPs by 10%
Annual limit on non-EU economic migrants
Give parents power to save local schools due to close
Give voters power to sack MPs for "serious wrongdoing"
Scrap ID cards
MPs to get vote on repealing hunting ban
Raise stamp duty threshold to £250k for first-time buyers
Mr Cameron said he had taken the Tories back to the "centre ground" of politics, away from the "narrow focus" it had in the past: "We stand for society, that's the right idea for a better future."
The Tories' plan to block the bulk of Labour's planned 1% rise in National Insurance is in the manifesto. Mr Cameron said it would save more than 50,000 jobs and would make "seven out of 10 working people better off than under Labour".
Labour say Tory plans to cut "wasteful" government spending by £12bn this year to fund the policy are based on "fantasy" calculations and are reckless.
Mr Cameron said: "Labour say the economy will collapse unless they keep on wasting your money."
He accused the government of trying to "frighten" people while he presented an "optimistic" programme and would "trust" people.
The Conservatives could "make things better without spending more money", he said, and had radical plans to "help the poorest, protect the NHS, help people find work and support families".
"This is a manifesto for a new kind of politics," he said.
Among pledges in the manifesto are a community "right to buy scheme" - to allow people to protect post offices and pubs threatened with closure.
People would be able to get local referendums on any issue if 5% of residents backed it - and would be able to use them to veto high council tax rises.
The number of MPs would be cut by 10%, and ministers' pay would be cut by 5%, followed by a five-year freeze.
Parents and charities would be allowed to set up state-funded schools - based on a model used in Sweden - and "unaccountable" police authorities would be replaced with a directly-elected official to set policing priorities, budgets and strategies.
Mr Cameron dismissed suggestions that there was no demand for people to set up their own schools as "cynical".
He said a network already set up to help them do just that had been "inundated" with offers and there was a "huge appetite" for people to get involved.
Other pledges include raising the stamp duty threshold for first-time house buyers to £250,000, to raise the inheritance tax threshold to £1m, to freeze council tax for two years and a voluntary "national citizen's service" for 16-year-olds.
As well as pledges to reform out-of-work benefits, scrap ID cards and increase health spending, there is also a pledge for an annual cap on non-European Union migrants who are allowed to live and work in the UK.
And there would be a referendum on any future European treaty "that transferred areas of power or competences" from Britain to the EU.
BBC chief political correspondent Laura Kuenssberg said there were no new details of how the Conservatives would reduce the budget deficit - something the party have pledged to do "faster" than Labour, who say they will halve it in four years.
None of the main parties has definitively ruled out raising VAT and the Conservatives also do not make a pledge on income tax, which Labour have said they will not raise.
The business and economy section of the Tories' manifesto is its ideological and intellectual heart
But shadow foreign secretary William Hague told the BBC: "The plans we have don't involve raising VAT. We are not looking for tax rises. People feel over-taxed."
Ken Clarke, shadow business secretary, later told the BBC that politicians should be "ignored" if they make firm promises on tax, unless it is part of a Budget.
"So any politician who starts telling you firmly what he's doing in tax should be ignored unless he's Chancellor of a very good budget," he said.
The UK Independence Party has launched its own manifesto, called "empowering the people", and has pledged not to field candidates against any "committed Eurosceptic" from other parties - including six Conservatives.
Labour launched their manifesto on Monday, pledging a "fair future".
Gordon Brown said there was a "complete hole" at the centre of the Conservative manifesto and it showed the party "hasn't changed".
"There is nothing in it to help the recovery. Indeed their measures would put the recovery at risk," he said.
"They are saying you are on your own. They are leaving people on their own to face the recession."
Lord Mandelson - who is heading up Labour's election strategy - said a "do-it-yourself" agenda for public services would not work "unless the frontline is properly protected and properly funded", and said Tories would "cut spending very sharply" to fund all their pledges.
Lib Dem leader Nick Clegg, who will launch his party's manifesto on Wednesday, said: "It's a manifesto of style over substance, you can't trust the Conservatives when they want to give tax breaks to double millionaires, not tax breaks to everybody else."
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