Plaid Cymru leader Ieuan Wyn Jones's election message
Plaid Cymru's leader has said "it is time to take responsibility" after 12 years of excuses under Labour.
Ieuan Wyn Jones told his party's spring conference it must "transform Wales".
The assembly election on 5 May was an opportunity to stop Labour managing decline in public services, he said.
Plaid would insist the next 10 years are a "decade of delivery", he told delegates in Cardiff. Mr Jones has been Deputy First Minister in the coalition government with Labour since 2007.
He joked that the two parties had "started divorce proceedings" as they part company to fight May's election.
But in an attack on his coalition partners, he said: "A vote for us on 5 May will ensure that the culture of excuses which has been fostered and bred by the Labour Party for most of the last 12 years will come to an end."
He said Wales needed a government that would stand up to Westminster and Brussels when necessary, but was willing to work with others when the time was right.
"My message to the people of Wales is that it is time to take responsibility. It's time to stop shifting the blame," he said.
"It is time for an end to the culture of excuses which has tarred Welsh government under Labour for most of the past 12 years.
He addressed an audience of the party faithful in a rehersal room at the Wales Millennium Centre, a stone's throw from the assembly in Cardiff Bay.
They applauded a list of Plaid successes in government, including legislation to protect the Welsh language and this month's referendum on direct law-making powers for the assembly - a key commitment in the Labour-Plaid coalition deal.
The speech put education at the centre of Plaid's campaign for the election - a portfolio held by Labour throughout the four years of the coalition.
Raising standards would be the main priority of a Plaid government, Mr Jones said, pledging to concentrate resources on ending illiteracy among primary school leavers.
Recent test results for 15-year-olds showing Wales had slipped down an international league table were "unaccaptable".
He hailed Plaid's plans for the economy, including a proposed not-for-profit company that would fund public infrastructure projects.
Responding to attacks from opponents - who say the plan is not feasible - Mr Jones claimed it was a "bold idea and we have the ambition and the determination to make it happen".
Plaid was not content to "sit back and settle for a situation where people go out of work", he added.
The speech also attacked spending cuts by the UK government.
Although he has stopped short of explicitly ruling out talks with the Conservatives and Liberal Democrats if May's election is inconclusive, Mr Jones has said it would be "difficult" to form a coalition with them in the assembly because of their parties' actions in Westminster.
But Labour has sought to claim that Plaid is prepared to deal with the Tories.
Labour MP Nia Griffith said: "Only one party in Wales has ruled out any deal with the Tories and that is Welsh Labour - the true party of Wales."