It's not like progressives haven't been shouting the answer to this for the past 20 years, but here it is again from an apparently recent convert from within the Democratic establishment camp.
Voters to Elites: Do You See Me Now?
What it doesn't look like is campaigning with Liz Cheney. It doesn't look like sending Bill Clinton to Michigan to lecture Muslims on how important it is to fund Israel's genocide. It doesn't look like Biden's garbage gaff. It sure as hell doesn't look like Harris having no answer to the question of how she would break with the Biden administration. All of these failures might have been irrelevant were it not for 50 years of Democrats looking down their nose at working Americans. A lot of it is policy, but a lot is just a failure of messaging.
It's certainly not obvious to many within the Democratic establishment sphere. historic_flawlessly_run_campaign
Exactly what it should look like next time is hard to say because it will to a large extent depend on the candidate and what issues have the public's attention. There certainly should be a lot more engagement with independent media. Progressives had an early lead in that area, but that was mostly quashed by a coalition of Republicans and Democrats threatening regulation to get social media companies to dis-empower independent news in favor of corporate controlled sources. Republicans then spent a fortune promoting right wing channels while Democrats did nothing. This goes to the root issue that Republicans seek out engagement with their base, while Democrats avoid it as much as possible.
Another thing would be for Democrats to drop messaging with technocratic measures that don't sync up with how voters feel about the economy. While the economy is technically in good shape, a lot of voters in any economy will be suffering. The message received becomes "we don't plan to change our approach regardless of how the economy is working for you." When interest rates skyrocket, the impact doesn't go away once they are back under control. When inflation skyrocketed, Democrats tried to minimize the issue when they should have mirrored the outrage and focused on how Trump policies created it.
In the big picture, Democrats need to get serious about going after wealth inequality. This improved somewhat with Biden, but Biden was incapable of selling it, and Harris barely tried. She let Trump take the lead on working class economics and had to chase the "no tax on tips" and "no tax on Social Security". Playing catch-up just made her look insincere. (Yes, ironic given Trump)
The American middle class has been under siege for decades, and they know it. It's human nature that they need someone to blame. Republicans hand them immigrants, LGBTQ+ and DEI. Democrats step in on the defense, but they offer no competing villain. They could tell the truth and show how corporate money and Billionaires have bought legislation to give themselves an advantage over consumers, but Democrats don't want to do that (for reasons you can speculate on). Democrats won't even go after clear cases of Republican corruption with any level of conviction.
The town hall meeting Bernie did on Fox was a great example of how Democrats can reach a right wing audience with left wing rhetoric. Running to the center never works, but speaking to their struggles and frustration in a real way can.