Writing in the Daily Telegraph, Michelle Ballantyne claimed Tory activists spent most of their time on the doorstep railing against another independence referendum, instead of laying out their vision for Scotland.
The South Scotland MSP said that if she is elected leader ahead of rival Jackson Carlaw - who was in charge of the campaign for the December 12 poll north of the border - she will "end the policy vacuum".
'Ordinary people do not care about marches'
She wrote: "We failed to put forward credible proposals for fixing the public services that have been grossly mismanaged by the SNP Government.
"We failed to give hard-working people a reason to vote for us beyond our commitment to safeguarding Scotland's place in the UK.
"Ordinary people do not care about flags or marches. They care about good schools, compassionate healthcare and safe communities.
"I am a proud unionist, but I did not get into politics to talk endlessly about the constitution.
"I am driven by the need to improve the lives of those around me. I know that Scottish Conservatives across the country share this drive."
Ms Ballantyne went on to lay out five policies she would enact as leader, including reducing admin workload on teachers, recruiting 2,000 more police officers, bringing income tax levels into line with the rest of the UK, cutting land tax for first-time homebuyers, and setting up early intervention schemes in deprived areas.
She is considered the outsider in the race for the Tory leadership, with Mr Carlaw boasting the support of a majority of MSPs, all of the party's Scottish council leaders and a number of MPs - including former Scottish secretary David Mundell.