At the federal level, drag out everything and block everything you can. Their margins in the house, should it be called in their favor, will be extremely narrow. Let them in fight and flame against each other. Use every procedural rule to slow stuff down. Filibuster everything. Even if a specific issue is a losing fight, make them have to fight it so they cannot move on to something else. Republicans have used these tricks to block progress for a long time, time to flip it back on them
At the state level, we can much have more room to push back. A lot of what they are likely to pull is pushing things back into the states. Codify everything at state levels. Ensrhine our rights into state constitutions. A lot of federal operations rely on state government cooperating behind the scenes. Without it, a lot more can be slowed way down or made much more difficult
Outside the government, we still have power as individuals. Organize unions, protests, etc
Do not give up the fight. Make every little issue a drawn out fight so they cannot move on to the next thing
Despair and hopelessness are what they want you to have. They want you to let them take it away without any resistance. Don't give in