Voters in four of the constituencies the Lib Dems cannot afford to lose in the next election have said they cannot take the party seriously.
Student Felix Kankwamba said he can no longer trust Nick Clegg over his U-turn on tuition fees.
While Brian Roberson said the new policies Clegg was promising, including the introduction of waiting times for the mentally ill, was "purely for elections".
ITV News Political Correspondent Romilly Weeks has this report:
As the conference season comes to an end, Nick Clegg had to prove he had some fight left in him after his U-turn on policies such as tuition fees.
In what some billed as his "best speech yet", the Lib Dem leader blasted the Tories saying the country does not want a party running it which "only looks after its own kind".
He further pledged to introduce national waiting times for those with mental health issues.
But tomorrow's by-election vote in Clacton, which could see the first Ukip MP getting into parliament, could change the political dynamic all over again.
ITV News Political Editor Tom Bradby has this report:
Justice Minister Simon Hughes has described Nick Clegg's conference speech as the Lib Dem leader's "best ever".
"He has been in absolutely top form all week," Mr Hughes said.
In contrast, he claimed the Labour conference had been "flat as a pancake" with a "disaster" of a speech from Ed Miliband, while the Tory conference had been characterised by "very nasty policies".
Labour's deputy leader has hit out at Nick Clegg after his conference speech, accusing him of being "desperate" to justify working with the Tories.
Harriet Harman attacked the Deputy Prime Minister over his suggestion that the Lib Dems should be judged by their achievements in government.
"Nick Clegg was right about one thing in his speech - the Lib Dems should be judged on their record. It is a record of broken promises and weakness.
She said Mr Clegg was "trying desperately to justify the decision he and his party took to back the Tories all the way".
Addressing party activists in Glasgow, Liberal Democrat leader Nick Clegg said:
Someone has to stand up for the liberal Britain in which we and millions of decent, reasonable people believe.
For tolerance, compassion, openness, unity - the values this party holds so dear.
If the Liberal Democrat voice is marginalised in British politics, our country will be meaner, poorer and weaker as a result.
We must not and cannot let that happen. We must make our voice heard.
Nick Clegg has urged voters to give the Liberal Democrats another chance, after admitting his party have been tainted by government.
The Deputy Prime Minister acknowledged that he was "no longer the "untainted... fresh-faced outsider", vowing to learn from the "mistake" of his infamous U-turn on university tuition fees.
"How will you judge us? By the one policy we couldn't deliver or by the countless policies we did deliver in Government," he said at the party's conference in Glasgow.
Mr Clegg claimed his was the only party who stood up for "decent British values" against "un-British" politics.
Nick Clegg has accused Home Secretary Theresa May of "playing party politics with national security".
"Stop playing on people's fears simply to try and get your own way," Mr Clegg said in his conference speech.
"Your Communications Data Bill was disproportionate, disempowering. We blocked it once and we'll do it again," he told Mrs May.
Comedian Al Murray has distanced himself from Nick Clegg's praise for his comments during the Scottish referendum campaign.
Clegg said the "Pub Landlord" had struck a chord by noting there was something "wonderfully vague about being British" in the lead-up to last month's poll.
But Murray quickly took to Twitter to say: "This Clegg business is nothing to do with me."
ATTENTION WORLD'S MEDIA: This Clegg business is nothing to do with me.
He went on to offer the Deputy Prime Minister some policy suggestions.
DEAR NICK CLEGG: The Pub Landlord also doesn't want to pay his speeding fines.
DEAR NICK CLEGG: The Pub Landlord vows in his next government to raise the temperature 5 degrees by 2019 to "save Blackpool's tourist trade"
The Liberal Democrats will "borrow less than Labour but cut less than the Tories" to cut the deficit, Nick Clegg said.
"We will finish the job, but we'll finish it in a way that is fair," the party leader said.
ITV News Political Editor Tom Bradby tweeted:
Nick Clegg is dismissive of Labour, but vigorously - even venomously - critical of the Tories. Must have been enjoying coalition!