There are a couple viewpoints that might do with a little straightening out.
(tldr for this paragraph - Dem. candidates need to worry a lot more about other people besides Trump voters)
First there’s Democratic candidates in the generally unknowable future landscape of 2020 deciding who they’re going to be tailoring messages to. Those people have a base which is basically everyone who’s not a conservative Republican. The vast majority of people who voted for Trump were evangelicals and conservative Republicans. That Dem. base is really large - far larger than conservative Republicans, and within that base, they have many people to reach out to who will flee if they tailor their message to evangelicals and conservative Republicans. There were a few oddballs who voted Trump as well (white nationalists/hardcore racists who usually stay home, confused soccer moms, and people who were swayed by anti-Clinton propaganda), and they might want to reach out to some of them assuming you can define more specifically who those non-conservatives were. But they’d probably be better off trying to court African-Americans (who had poor turnout), Hispanic voters (who had iffy turnout, and swung to the GOP more than expected), and younger voters (who had poor turnout, and swung third party a lot). Those groups matter a whole lot more than Trump voters, since they’re part of the base, the Dems have policies that matter for them, and it’s easier to tailor a relevant message that doesn’t piss off the rest of the coalition. If we’re talking about that candidate, then those 63 million are way too risky to spend much effort on, other than trying to get them to see what a failure Trump is and how badly he’s betrayed them, only to try to get them to stay away from the polls (they’ll make terrible choices down-ballot too, so it’s much better if they stay home). But that’ll be up to whoever runs to sort out, and our idle 2017 speculations have value mostly as getting to hear ourselves yammer.
(tldr for this paragraph - random people have different situations, and maybe listening to Trump voters isn’t the best use of their time)
Then there’s the viewpoint of random citizens who have to live in the US with the minority of people who made a really terrible choice in voting for Trump. In that case, it’s up to the random citizen to sort out what their situation is and whether there’s any point in trying to reach out to some group of people. Personally, I’m stuck listening to some of them. I have heard them loud and clear. Immigrants are evil and need to be banned. Muslims are evil and need to be banned. LGBT people are sick, and ought to be banned somehow. Liberals are evil and need to be stopped by regulations on the press and education, and it’d be great is there was some way to ban them. Women are too uppity and need to be put in their place. Taxes on the rich need to be cut. Jobs need to appear by some kind of magical tax cuts and eliminating worker protections, environmental protections, and other regulations. Healthcare doesn’t matter and if you get sick and aren’t insured, you’re just irresponsible and should’t be expecting handouts. I spent hundreds and hundreds of man-hours before the election in a few forums talking to friends/people going over Trump but his supporters really were mostly authoritarians thrilled to get their strongman, and excited at seeing “liberals” and brown people get hurt since that was what most vocal Trump supporters were most focused on. IRL, my friends loathe Trump, and my conservative family members really doesn’t care about my political views since Fox is the voice of Truth, and in not supporting the GOP, I am a deceiver.
(tldr for this paragraph - for me there are definitely better ways to spend my time, esp. since some on the left are at war with the Dems)
So for me, as a rando, there’s stuff I can do, but listening to and talking to Trump supporters is pointless, and every one I’ve spoken to is so blinded by an ideology built on hostility to progress and anything Liberals like, and so misinformed and ignorant (usually willfully) that it’s not worth my time. There are leftists who were so disenchanted by the Democrats, largely thanks to a very well orchestrated Russian propaganda campaign via Wikileaks, that they refused to support Clinton. Those people were worth spending time on. There’ll be a few more leftists in 2020 who are prone to moral equivocation between the lesser evils of Dems and the greater evils of the GOP, who believe votes “send a message” rather than select a candidate, and who will be motivated to choose personal purity over choosing to prevent harm to others, and I’d be more useful chatting with them, since we share a lot in our basic outlook (and tribal characteristics).
In terms of things that would be helpful, I’ve set up monthly donations to Planned Parenthood, the ACLU, and the NRDC. I’m going to protests. When 2018 comes up I’ll be volunteering with the local Dems., and again in 2020. I’m making my voice heard in whatever ways seem relevant. Those things seem like they’ll help. We really all should be focused on worrying about the shit going down now, since 2020 is a long way off.
If you’re in a different situation and can reach out to some Trump supporters who can be turned around, that’s great - go for it. There are other things you can do that will help more, but every little bit counts, and everyone’s different kinds of contributions add up and matter. Just stop telling me how to do my job, and please stop imagining we haven’t listened to Trump voters, because I hear from them literally every single day. I listen, I disagree, and I see that in my case there’s nothing I can do to turn them around. Also please stop offering shitty advice to Democrats who have a whole lot more people than Trump voters they need to win over if they want to take 2020.