Personally I'm not too worried it was a close race and a lot of people are not awoken by how much their vote means. Trump was an odd and remarkable candidate and he won, but by all evidence he won't be re-elected (granted I could be wrong). I think dem's have to grin and bear it, support him when its reasonable to do so, block him otherwise, and just wait for the next one. I don't think dems should overlook 2018 senate races in any sense and I am sad they don't fight for state houses as well.
Population dynamics are slowly turning in favor of the democratic party as well who are growing their base. I think something that is underplayed is what's happening in deeply red, populous states like georgia, texas, and arizona which are now turning slowly pinkish. The margin of victory in texas has slowly been dropping. In 2004 it was 30 points, in 2012 it was 15 and in 2016 it was 10% as the cities become larger and bluer. Alabama for example has been steady being between 25-30% percentage points in favor of the GOP.
I think this is a real danger for the GOP and something to capitalize on for the democratic party. They lost texas by 800, 000 votes in a state that houses 38 million people and has what 38 or 39 electoral college votes. There is a county in houston alone that has 4.5 million people and it went blue 2:1 in terms of the voting electorate with about 15 percent of the total population actually voting and 50% percent of the registered voters showing up. Why not go hard, all in and try to win Texas as opposed to trying to win a bunch of small states or fickle states here and there. I think that's the magic of trump's campaign. He picked a demographic and went hard at them.