1. Expand Beto's voter registration and get-out-the-vote activities to all red and purple states to improve youth participation. He proved it can be done, but there'll need to be something to keep the young voters engaged once Trump is gone.
2. You're not going to get a constitutional amendment to abolish the Electoral College. A better answer is to modify the Reapportionment Act of 1929 so that there are more Representatives (and thus more electoral college votes) to better represent the popular vote and the differences in state populations. This doesn't require a constitutional amendment.
3. A new voting rights act to eliminate gerrymandering and all the other nonsense that's been going on. I'm not sure the federal government can actually require states to do vote-by-mail for all registered voters the way Oregon does, but it would be nice if that was implemented by more states.
4. People overwhelmingly like progressive policies when they are presented in isolation, and yet they go on to vote for candidates who are against those policies. Democrats need to get better at messaging those specific policies in bullet point form, and linking them to their candidates. Lots of memes? I don't know the answer, but there's got to be a way to do it. Voters don't need dozens of pages of policy; they need five bullet points they can get behind. (I'm backseat driving here, without any experience in this area myself--I'm sure people are already doing this, but somehow we need to do it better.)
5. Stop using the word "socialist". It doesn't mean anything. Or rather, it has too many different definitions to use it any sort of meaningful way. Since everyone uses it in completely different ways, they're all arguing past each other about something other than the topic they think they're talking about.
6. I don't know what can actually be done at the governmental level about the media, but the media needs to do something itself. Maybe start by pressuring them to call out obvious lies from spokesmen, rather than just printing those lies verbatim, and without comment, in their stupid "let's present both sides equally" paradigm. Maybe don't have talking heads on that you know are going to spew nonsense--it doesn't matter if your other talking heads are arguing against them; you're still giving voice to the nonsense and propagating it.