The Prime Minister has admitted he faces "a hard road to success" when he returns to work after his summer break.
Writing in the Mail on Sunday, David Cameron says he will be concentrating on tackling the country's economic problems.
He also addresses some of the controversies that have come up during the parliamentary recess.
"Yes, growth has been disappointing - but in the past two years we've also seen more than 900,000 jobs created in the private sector.
"Yes, turning around our schools is tough - but hundreds of new free schools and academies are opening every year.
"Yes, tackling welfare dependency is difficult - but there are more people in work now than at the last election."
Parliament returns on Monday after a six-week recess, and Mr Cameron insists he will not take the "easy road" when deciding policy.
"The easy road on education is to cave in to the unions who want to keep inflating the GCSE and A-level grades and pretend that standards are rising each year.
"The easy road on welfare is to spend more money, push people a pound or two over the official poverty line and pretend you've cracked the problem. But it's these easy options that have betrayed millions."
He added: "It will be a hard road to success - but that's the road we must take."
Sky's political correspondent Sophy Ridge said: "David Cameron does seem to be taking on his critics in this piece for the Mail On Sunday.
"He has just got back from holiday, he's essentially saying, 'Look (Munich: 867225 - news) we’re going to crack on with business from tomorrow onwards and we're going to really focus on getting Conservative proposals back.'
"I think that's what a lot of his backbenchers have been accusing him of, of not being Conservative enough, of being too wimpy in front of the Lib Dems."