Get out in the streets, make noise, alert your neighbors, call, text, message everyone you can think of. Go out and record everything that's going on, but be safe about it. Try to get license numbers and clear shots of any faces. If someone is being detained, try to get their full name, write it down. See if they can give a phone number of someone to call.
Second, honestly, first amendment the hell out of it. Don't get into a fight, but let them know exactly what you think about them, loudly. The more noise you make, the more attention you'll draw.
As a resident of Minneapolis I hate that this is our reality now, that I never leave my house without a whistle, a fully charged phone, and my bullhorn, but its what we have to do to to protect our neighbords, our community.
Anyone in the area, if you're not feeling up to getting up close and personal and potentially getting teargassed or pepper sprayed, go on down to the Whipple federal building and make your voice heard. There's something about the sense of community outrage there that's very cathartic, it helps you feel like you're not alone. There's people handing out hot cider and cocoa, and there's snacks and handwarmers, and someone will definitely let you get it out of your system with a bullhorn if you want to.
The looks in the eyes of the ice agents as a crowd of hundreds of people shouts at them to quit their job and calls them cowards for wearing masks is priceless. They fear us, as well they should.