Ms Truss was at Ludlow Racecourse to appeal for votes from Conservative members in the region, following leadership rival Rishi Sunak's earlier visit.
When introducing her on stage, Ludlow MP Philip Dunne - who had not yet declared his favoured candidate - said: "We've had the entrée, now for the main event."
His comment was met with some "oohs" and a few chuckles before Ms Truss addressed the audience.
She said: "It's fantastic to be here this afternoon. I grew up in Paisley in Scotland and Leeds in Yorkshire and attended the local comprehensive. There were too many children who were let down by lack of opportunities. That is one of the reasons I got into politics.
"We're a great country. We should be an aspiration nation. We face very difficult times. We've got the economic crisis after Covid, and the war in Ukraine
"Now is not the time for business as usual."
Ms Truss added: "I want to unlock all of those post-Brexit freedoms by the end of 2023. I want to lower taxes. I think it was wrong to raise National Insurance.
"I also want to remove the green energy levy to save people money on their fuel bills.
"I want to keep the corporation tax low. If we raise it we will make our country less competitive
"I'm on the side of people who work hard and do the right thing."
Ms Truss also said she would abolish the Government's top down housing target, and wants to remove bureaucracy for farmers, a suggestion which raised a cheer from the audience.
She said: "We've been together [with Philip Dunne] to a lamb farm near here and I know this is an agricultural powerhouse.
"I will make sure we level up our country. I get that rural areas have been left behind in terms of mobile phone signal and broadband."
She also said she wanted to increase defence spending, and protect single-sex environments including domestic violence refuges and toilets in schools.
"I believe our best days are ahead of us. I think we are a force for good in the world," she said.
"We need to be proud to be Conservative. I know we've taken a battering recently, but people have voted for us because they agree with our values.
"I know that with a positive vision for the future of our country we can beat that plastic patriot Keir Starmer. We can build a greater Britain and make sure the United Kingdom succeeds."