Sign Some Petitions
Petitions require a very limited amount of effort, however they do provide a sort of "temperature check," on the size of a population that supports a given initiative. Add your name to the tally where relevant
Demand Congress continue funding Affordable Care Act subsidies: 45 suggested that he and other Republicans would begin acting to undermine healthcare for Americans by cutting off funding for the ACA's subsidies for lower income consumers.
Tell the Department of Homeland Security to Reject Invasive and Unnecessary Social Media Travel Proposal: DHS is considering the adoption of an invasive procedures for travelers entering the U.S. that would force certain travelers to provide the passwords to their social media accounts in order to get through Customs.
Kamala Harris' Petition on The Paris Climate Accord: 45's administration is discussing "whether to recommend  withdraw the United States from the Paris climate accord." The Paris Climate Accord is a historic agreement seeking to reduce carbon emissions signed by almost 200 countries.
Social Security: Tell Congress “Social Security should be expanded, not cut. Oppose any tax reform plan that would eliminate the Social Security payroll tax or otherwise pave the way for future cuts to Social Security benefits.”