The world of competitive sports teaches many life lessons. The democratic party needs to learn what every coach recommends after a terrible season: Get back to the basics!
Democratic fundamentals include a keen awareness of how our system of government works: it favors the majority, but gives some power to the minority. The house is where all "purse string" issues originate. The senate filibuster can be used for many things, but not the budget.
Fringe issues are not important for the next two years! Defend the new deal, medicare, medicaid, the aca; support increase in minimum wage; fight to modify the voting rights act!
Bottom line, get out to vote, and get everyone you know out to vote. Stop whining about the party not being sufficiently progressive, and settle for the most progressive person who is electable! (Even if it is a blue dog!)
Speak out against those who encourage non-participation! Speak out against those who deny science! Do not tolerate racism!
The democratic party has empirical evidence on its side - use it!