Taking it slow
Trump has made some of the most disastrous nominations in history. Many of his nominees are extremists that are ideologically opposed to the purpose of the agency they have been nominated to represent. For example, Betsy DeVos is the Secretary of Education even though she has fought to privatize the public school system. Scott Pruitt is perhaps the worst. He's an avowed climate change denier supported by the fossil fuel industry who has spent his career fighting against the EPA - and now he's leading the agency. Some have complained that Senate Democrats have not done anything to fight back against this; however, they are actually setting records in fighting presidential nominees and delaying their nominations. The filibuster is gone, thanks to Harry Reid, but they can still bring the Senate to a crawl:
Under the new Senate rules a determined minority can still require 30 hours of debate even after a cloture vote, which closes the discussion. Using this procedure on every nomination would actually require more time than the Senate works in an average presidential term.
Delaying nominations that will ultimately succeed may not sound like much, but it's making a big difference where it counts: stopping the radical far-right Republican majority from enacting Paul Ryan's conservative granny-starving utopia:
As Trump’s personnel are delayed, he is losing ground on policy. That’s in part because when the Senate is consumed with every nomination fight, it is not debating Republican legislative priorities. Time is the most precious commodity in the Senate. Every new administration is inevitably judged by the accomplishments or lack therein of the first 100 days.
Every moment spent on confirming Cabinet nominees is a moment not spent on the Republican agenda. Every ounce of executive and legislative energy spent on a Cabinet nomination is effort taken from other priorities.
Faced with an authoritarian president enabling a radical right-wing agenda, after 8 years of scorched earth opposition to Obama even during a national crisis, these kinds of techniques are justified. It's more important to preserve our democracy than to play nice with the likes of Mitch McConnell, who quipped during the chaos and human suffering of the Great Recession that the biggest priority for Republicans was to make Obama a one-term president.
Indivisible has a great article on the power of every Senator to stall Trump's agenda by withholding consent and filibustering