I read a blog post by Robert Reich the other day calling for resistance to Donald Trump's agenda as President. It's disappointing that none of it included trying to work with the new administration.
I agree with very little of Trump's agenda, or the way he does business. So I understand why Reich and other liberal voices are calling for opposition. That blog post also includes some good opposition concepts, like (peacefully) protesting or expressing your views through letters and social media. But obstruction tactics are just a way to keep anything from being done, and the more they're used, the more likely they'll continue to be used when the balance of power shifts back.
What the political opposition voices need to be calling for is looking for ways to positively influence the Trump administration via compromise. There will be policies and legislation enacted that we don't agree with, that's a given. There will be a repeal of at least part of Obamacare, and there will be tax cuts that favor the rich. With Republican control of both Congress and the Presidency, those kind of changes aren't avoidable.
However, the Republicans are no more united now than the Democrats were back when they had control of Congress and the Presidency. If the leaders aren't willing to make compromises, then they won't get far since their own party isn't united. Democrats willing to work with the administration and congressional leadership will be able to find ways to include compromise positions. It won't be easy - nothing in politics is - but I'd rather see something done over trying to simply block everything.