The only elections the DNC will be winning will be purely because of how terrible Trump is. They could do nothing and everything would probably go better for them than whatever they actually do next year.
I think that's symptomatic of the problem. Conservatives turn out in large numbers to support their own belief structures. Liberals just stay home.
What makes the GOP successful is that they understand their constituencies' beliefs and they cater to them. The Democrats don't seem to understand that their constituents have a huge spectrum of beliefs and that many of them conflict. So the Democrats rely on saying "You need to vote so that the other guy doesn't win!" So disillusioned Dems stay home because no one is "looking out for them anyway."
As a party, the Democrats are spineless and refuse to take a stand on anything. Campaigning on "We're not Trump" is going to lose them the midterms. They need new leadership immediately. Young leadership, at that. They need to stand for things that will make millennials get up early or stop on the way home from work to cast their vote. Right now, they don't have that. Just watch how many Republicans win their races on Tuesday.