Call public officials like
representatives, senators, governors, state reps, and local government. Especially if Republican (Democrats and Third Party don't get a free pass though) and make your voice heard. Let then know you're keeping an eye out whether they stick to following Trump or resist him. Look up their backgrounds and tell them why they should resist Trump based on their own past statements, especially if they condemned Trump before his presidency. Reading a script someone else makes works (especially with phone anxiety), but writing a script has more impact. Be polite, but firm. Express disappointment (like a parent) rather than anger (like certain parents). Keep in mind when you call that you will likely speak to a secretary or office worker who will forward the message, rather than speaking directly, so do not get mad at them for doing their job so long as they remain civil with you (and even then be the bigger person). Also do not ever threaten anything, even vaguely. About the worst you can say is "I look forward to casting my vote in the next election". Do not be all "It would be unfortunate if certain things came to pass...". Don't be a twitter rando.
Condemn companies that profit off of Trump's backwards legislation and especially if they come to his defense as devil's advocates "not looking to make political waves". Uber has caught some flak for being non-commital to how they stand days before meeting with Trump that reads to most people as "does not want to get uninvited suddenly". Elon Musk has gotten into trouble after supporting Rex Tillerson and apparently has a pipedream that Trump will support a Carbon Tax even thoughit was dismissed with lukewarm reception at his meeting with Trump earlier this week. Pay attention and while you do not want to boycott everything (including food) determine which boycotts you can fully stand behind without impacting your quality of life any more than Trump is threatening it, and anything you cannot boycott, try to offset by supporting companies that do stand up against Trump (be wary of people paying lipservice to gain brownie points though).
Donate cheddar to the ACLU which has gotten a temporary hold on the Muslim Ban order while the courts sort out how lawful it is. Donate to whichever groups support your interests (but be mindful not to give it to disingenuous groups out to profit from the waves of donators. Give something to Planned Parenthood if you can because they're floating their employees the best they can right now, and as someone with a couple of family members who work for PP I can tell you it's appreciated by them to continue to do important work as long as they can hold out.
And most importantly, stay mad but healthy. Keep track of what Trump says, but pay attention to what he does so you won't be fooled while he's blathering about whatever inane thing. Take breaks when you need to from the stress of it all. A day or two away from constant surfing about the latest news won't hurt you. And be sure to do your best to get some sleep. Sometimes that's hard with stuff going on, but you can't be at you best if you don't take time to rest.