That's kind of a broad question, and there's at least two contexts in which I can answer it. One is on a personal level, and one is more on the level of "what should the DNC do if they want to win another election".

Personal answer first. Quite simple:

• join a union

• engage in mutual aid

• read theory (yes really)

• local politics (no matter how local) matter, act like it

• vote for politicians and their policies because you believe in them, not because other guy bad. If your choice is between Hitler and Hitler wearing a funny hat, voting uncommitted is not only your democratic right, but your duty. If you guarantee your vote to a politician regardless of what rhey do or advocate for, the politician has no reason whatsoever to listen to you or cater to your needs. None.

Now if you're asking as a card carrying DNC member with influence:

• Do not capitulate to right wing framing. You will never win at being right wing, the right wing is much better at that than you. Concretely, engage in counter messaging. For example, when it comes to undocumented immigrants, frame them as a boon to society (which they are) and aggressively fight anyone who claims they commit more crimes (they don't, in fact they commit fewer per capita), don't say "I agree mr republican, and my border policies are just as draconian as yours, if not more, just as they should be!" Same with fracking, genocide, crime, taxes, etc. Be an alternative, not a weak derivative.

• Don't fund a genocide. So easy. All you have to do is not send 17.8 billion in military aid to any country committing a genocide. You see a country committing genocide? Do not send 17.8 billion dollars in military aid. If you can't help yourself and have to send the money anyway, don't go bragging about it on your campaign trail, you fucking idiot. More generally, people do not like war, and prefer not to spend billions on some country they've never been to. Trump managed to position himself as the peace candidate TWICE because the dems kept falling over themselves to prove how fucking hawkish they were. This is pure incompetence.

• Start advocating for worker's rights. Stronger unions, higher minimum wage, forced and paid parental leave, paid sick leave, and so on. These are deeply popular positions, as polling shows, also among people who normally vote republican. A one time tax credit is not worker's rights.

• Start advocating for universal health care again. Or at least fucking mention it every now and then. The US is the only nation in the developed world (and beyond?) that doesn't have this, you can gain so much on this.

Follow these simple steps and you'll win your next election!