The Liberal Democrat leader said his party could provide stability but warned that Labour and the Tories were in danger of “sleepwalking” to a “messy” minority government.
Mr Clegg, who was travelling to John O’Groats on the final leg of his tour of Lib Dem battleground seats, claimed Ed Miliband and David Cameron refused to admit neither of them would win an outright majority.
The Lib Dem leader, who has refused to share power with the SNP or Ukip, has indicated he would not form a minority coalition that depended on the votes of Nicola Sturgeon or Nigel Farage’s party.
Confirming that he would walk away from government if he could not get a suitable deal for his party, Mr Clegg said: “You should never, in politics or in life, want to cling on to power for power’s sake.
“We want to do what we think is right for the country. We put the country before our party before - it was the brave thing to do, it was the right thing to do - and we would do it again.
“That contrasts with the attitude of David Cameron and Ed Miliband who are still seeking to claim that they are going to win a majority when they know they are not and are in real danger of sleepwalking towards a messy, unstable, minority government which is basically held captive by the extremes on right and left.
“That is not what our country needs.”
Speaking in Kendal, Cumbria, as he continued his 1,000-mile trip from Land’s End to John O’Groats, Mr Clegg said he was confident his party would save enough seats to make it a key player in any negotiations after polling day.
“I’m really confident that we are going to do much better than all the endless pessimists have predicted, much better,” he said.
“If you want a stronger economy and a fairer society, if you want a party that won’t cut as much as the Conservatives and would borrow less than Labour, then the Liberal Democrats are the only party to provide that stability.
“That’s what I think a lot of people in the latter stages of this campaign are looking for.”
Labour leader Mr Miliband has pledged to scrap the non-dom tax status if he wins on May 7 and has indicated that its abolition would be non-negotiable for him in any post-election discussions.
Mr Clegg refused to be drawn on the Labour “red line”, insisting he was focused on his own demands.
“I’m not going to provide a running commentary on other parties’ red lines.
“All I’m saying is that the Liberal Democrats have a series of red lines which, unlike the Conservative and Labour parties, strike the right balance between doing what’s needed to balance the books but do so fairly, give people tax cuts, make sure that public sector workers don’t have to endure cuts to their take-home pay any more, invest in our public services, our schools and our hospitals, and protect our environment.
“That is what we will be focusing on.”
Mr Clegg has said his “very strong preference” after May 7 is for the Lib Dems to form part of a majority coalition rather than enter into an alliance which could face daily struggles to get legislation through the Commons.
Pressed on whether he would form an alliance with either the Tories or Labour that failed to deliver the required majority, he said: “A government has to govern, so you also have to have the means to govern.
“I have certainly made it quite clear that I am not going to enter into any pacts, deals or arrangements which would in practice mean that a government is on a life support system which can be switched off by Nigel Farage or Alex Salmond, so there you have your answer.”