She will say more about women's issues, be more open about her personal feelings and favour small, intimate encounters with voters instead of big rallies, says Gordon Giffin.
It will be a far cry from 2008, when she campaigned as a battle-hardened Washington veteran rather than focus on the historic nature of her candidacy, as the first woman with a real chance of becoming president.
It won't happen again, Giffin said Friday.
"There is no doubt that women's rights — women's issues, women and girls... will be front and centre in her campaign," said Giffin, the Clinton-era ambassador to Canada who worked on several Clinton family campaigns and accompanied her on recent trips to Vancouver, Calgary, Toronto and Montreal.
"I think last time, in 2008, there was, not so much in her mind, but the people around her had this view that for a woman to run for president they had to run and convince the country that they were just as strong as a man. So, in a sense, the fact that she was a woman and was interested in women's issues was understated.
"I don't think that's going to occur this time."
Clinton is expected to launch her 2016 campaign with an online announcement Sunday, followed by meetings with small groups of voters.
She's already begun signalling some differences from her 2008 loss to Barack Obama, where it wasn't until her concession speech that she said anything memorable about cracking the glass ceiling.
On Friday, she released an epilogue to her latest book, which delved into her feelings about becoming a grandmother. She described her experience as a working mom, in a recent Silicon Valley speech.
In that speech she saluted Patricia Arquette's wage-equality rallying cry at the Oscars — but added that the U.S. has so much more to do on sick days and paid leave. She's pointed out elsewhere that the U.S. is one of the world's only developed countries without a parental-leave program.
Clinton described her experience working in a small law firm when she got pregnant, and said nobody knew how to handle it because there'd never been a pregnant partner before.
''I just kept getting bigger and bigger and bigger. And I'd walk down the halls, and some of my partners would avert their eyes. They didn't know what to say to me," she told the California audience, a few weeks ago.
"So when the time came and I went in and gave birth, the next morning the lead partner called and he said two things: 'Congratulations,' and 'When are you coming back to work?' I said, 'Well, thank you very much, maybe in four months.' Pause. He goes, 'Oh. ... OK ...' But I was in a position where I could (request that). Too many women ... lost their jobs, they were marginalized, they were demoted for doing one of the most important jobs anyone in a society has: producing the next generation.''
Giffin expects to help out with the campaign, as a volunteer. His day job is on the board of the soon-to-merge, world's biggest law firm — Dentons and McKenna Long & Aldridge LLP, which works in Canada and the U.S.
He said some of the stylistic differences were already evident late in the 2008 campaign.
There was an emotional moment in New Hampshire when Clinton teared up and he said she opened up a little when it was too late: ''She won primary after primary after primary (following that),'' Giffin said.
''I think that's the person who's going to be campaigning this time.''