-cctv: they are far more sophisticated now, from high resolution to AI for automated classification and identification, assume there's a camera man following you all the time. Ring, Flock, etc. are all an interconnected surveillance system that's watching all the time. Some tech can even ID you with a mask, so better have a proper face cover that changes the bone structure. Also, don't use your car, it's useless to use your car with a mask only to be ID'd by your car on your way to the protest (btw, flock can ID your car even with no plate number), use a bike, walk, or similar, public transport is also monitored. Drones are already used by law enforcement, and they use systems like Aeroscope to detect other drones as well. Use an umbrella to block the drones, the more people use umbrellas the better to counter drone surveillance.

-if it's at night, have an IR cam cloakers or blocker around your face (like glasses etc.) to disturb the IR in cctv systems. Although a lot of new ones don't use IR but rather colored night view.

-cash: it goes without saying, your transactions will expose you. And leave all your IDs at home.

-clothes: if there's some organization among the group, an agreement about the clothes colors/type is better than each wearing unique clothes.

-don't share any info about your plans online or with people in the protest, as online everything can be retrieved, and in the protests you can't trust randoms there.