Play matchmaker for me: I'm looking for a person who voted Obama, then voted Trump.

[TBFProgrammer]

No, you're perfect.

If you've voted Obama and the democrats in the past, that means there was a time when they stood for, or against, something that mattered to you, and they lost your support.

Not really. 2008 was the first year I could vote for president. I really hadn't looked terribly closely at the candidates. All I knew was that I really didn't like a lot of what Bush had done and Obama was running on change. If I had followed things more closely, I might have been able to tell that the changes Obama would actually bring had little to do with the problems I saw in Bush.

what the Democratic party would need to stand for to re-earn your vote

You could try abandoning the war mongering in the Middle East. The US is grossly overextended economically and war is expensive. You could also reassert 4th amendment protections. Both of these would be positive changes to your platform from my perspective.

I can't speak to what will capture rust belt voters, as there are intrinsic problems with our economy that are going to be incredibly difficult to resolve. These problems are increasingly global and policy changes alone will not be sufficient to address them.