It’s been almost two weeks since their stinging defeat in midterm elections, but Democrats are still licking their wounds and trying to figure out where they went wrong. They don’t have much time to extract the right lessons: The 2016 presidential campaign will begin in earnest any minute now.

So I consulted two Democratic sages, each of whom played a central role in electing the last two Democratic presidents: David Axelrod, who worked for Barack Obama in 2008, and James Carville, who worked for Bill Clinton in 1992.

Their advice — aimed primarily at Hillary Rodham Clinton, who they both assume will run — boiled down to two basic precepts.

First, don’t take the 2016 election for granted; it’s wide open, and either party could win.

Second, the overriding issue on voters’ minds is the economy — specifically, the stagnant lot of middle class workers. The candidate with the most convincing remedy for that problem is likely to win.

Let’s take them in turn.

It may seem obvious that you should never take a presidential election for granted. But some Democrats have suggested their party has a virtual lock on the electoral college because more minority voters and young people will turn out in a presidential year.

Wrong, Axelrod said at a panel sponsored by the Wall Street Journal. Take no comfort in the demographics, he told the audience, because “history suggests it’s very difficult for a party to win after an eight-year run.”

There have been seven presidential elections in the last 60 years when voters could extend a party’s hold on the White House beyond eight years. They declined to do so six out of seven times. The sole exception was in 1988, when George H.W. Bush defeated a weak Democratic candidate to succeed Ronald Reagan.

“Of course people are going to want some kind of change,” said Carville. “No one is going to say: ‘I want the next four years to look like the last eight.’”

Lesson 2: the economy.

“We have to have a stronger message around economics,” Axelrod said. “The danger for Secretary Clinton is that, as was the case in 2007, her candidacy is out in front of the rationale for it. She needs to jump on that message and stay on that message.”

Carville thinks the former secretary of State has already figured that out: She just “needs to talk about it more. We have a lot of work to do. But there’s time.”

Indeed, Clinton has been talking about the economy — and sounding distinctly populist notes. In May she compared income inequality today to the “age of the robber barons.”

Stumping in Boston during the midterm campaign with Sen. Elizabeth Warren (D-Mass.), one of the Democrats’ toughest critics of Wall Street, Clinton said: “I love watching Elizabeth give it to those who deserve it.”

“Don’t let anybody tell you that ... it’s corporations and businesses that create jobs,” she added. (After Republicans howled, she said she had unduly “shorthanded” a more complex argument.)

It’s fair to wonder whether Clinton is thinking partly about fending off a primary challenge from candidates to her left, such as Warren. Her speeches have been long on empathy for the struggling middle class, but short on policy proposals to fix their problems.

She talks up a basic Democratic wish list — a higher minimum wage, paid sick leave, pay equity for women, pre-kindergarten education — but hasn’t added any new ideas. She hasn’t endorsed any of the reforms liberal economists have been batting around for reshaping the tax code, such as a hike on upper-bracket earners to pay for tax cuts at the lower end.

Of course, it’s unfair to expect a non-candidate to roll out a detailed economic platform. Even Clinton should be allowed to decide to run on her own timetable, no matter how desperate her supporters are to see her in the race.

But she still faces the challenge of meeting voters’ appetite for change: showing how she would be different from an incumbent most voters say they’re tired of, especially when her policies aren’t all that different from his. How does Clinton turn into a fresh new face?

“Simple,” said Carville. “She’s not Obama. She can say, ‘Look, I ran against Barack in 2008.’”

Axelrod suggested that Clinton accentuate stylistic differences: less nuance, more bluntness. She did that to great effect, he noted, in the later stages of her 2008 primary campaign.

“She was much more visceral. She was closer to the ground. If she can be that candidate in 2016, she will be a much stronger candidate. She has to throw caution to the wind.”

They almost make it sound easy. But Hillary Clinton, despite her supposed advantages, may soon face an unexpectedly difficult challenge: turning a familiar message into one that looks like change voters can once again believe in.

Doyle McManus is a columnist for The Los Angeles Times.