After being criticized for his debate performance, Donald Trump is hitting back against Hillary Clinton with a new strategy.

Trump prepped lightly​ for the first presidential debate. Now, he’s cramming and he’s doing it in full public view.

The Republican presidential nominee is working on several new attack lines and themes against Clinton, test-marketing them as he travels from rally to rally. It’s all part of an effort to make Clinton’s fitness for office – not his – the central part of the campaign, reports CBS News correspondent Major Garrett.

“The only people Hillary Clinton ever fights for are the special interests who write checks for her -- big, fat, beautiful checks,” Trump said.

Trump portrayed Hillary Clinton as relentlessly corrupt, alleging pay-for-play schemes while she was secretary of state.

“She put the office of secretary of state up for sale, and if she ever got the chance, she’d put the Oval Office up for sale also,” Trump said.

There’s no proof to support Trump’s accusations. Still, he began marketing a new catchphrase.

“With her it’s about ‘follow the money.’ Remember that phrase,” Trump said. “Remember this phrase: Follow the money.”

Trump mocked Clinton’s health and her fainting spell -- one the campaign later blamed on pneumonia.

“Day off, day off, day off... all those day-offs and then she can’t even make it to her car. Isn’t it tough?” Trump said.

In an interview, Trump also waded back into the dustup with former Miss Universe Alicia Machado​ over her post-pageant weight gain, claiming, “I hardly know this person.”

“They know what they’re getting into. It’s a beauty contest,” Trump told Fox News’ Bill O’Reilly in an interview.

This came after Clinton accused Trump of bullying Machado at Monday’s debate.

“He called this woman, ‘Miss Piggy,’” she said.

On Wednesday, Trump pointed to the beauty queen’s troubled past, and said he was only trying to help.

“But they wanted to fire her, I saved her job, because I said that’s going to be ruinous and I’ve done that with a number of the young ladies where I saved their job,” Trump told​ O’Reilly. “And you know what happened? Look what I get out of it. I get nothing.”

Trump predicted the Machado case could backfire on Clinton. Machado was implicated in a 1997 murder in Venezuela and accused of threatening a judge. Ultimately, charges were never brought on either count.

Trump appears willing to relitigate the Machado saga, even though some post-debate surveys indicate it has damaged his image with women voters.