Here is a post from Balloon Juice giving helpful hints about protesting, and safety precautions that you might consider taking.

Peaceful Assembly and Personal Security – Re-upped
by Adam L Silvermanat
11:05 am on January 15, 2017

I know a number of you all are planning to join one of the marches that will begin taking place between now through, and then after, the inauguration. So I wanted to re-up the post for anyone that missed it the first time.

Congress shall make no law… abridging…the right of the people peaceably to assemble, and to petition the Government for a redress of grievances. — Amendment 1, Bill of Rights, US Constitution

One of our readers/commenters emailed me about a week ago and asked if I would put up a post about personal security for those going to peaceably assemble to petition the Government for a redress of grievances. I put a list together and ran it past a select group of our Balloon Juice legal eagles (those I’ve corresponded with before/have corresponded with me, so if you didn’t get asked, don’t be insulted I didn’t want to just impose on you with a cold request) – thank you all for getting back to me. Here’s my list of what I think anyone going to peacefully assemble should do to enhance their personal security.

1. Go with a buddy, that way you have at least one person looking out for you/watching your back and vice versa.
2. Carry cash and make sure to carry a valid picture ID!
3. Bring a pocket flashlight.
4. Get and wear a go pro that is automatically updating to the cloud.
5. Bring a pocket charger for your cell phone and go pro regardless of whether it is supposed to be a long day.
6. Make sure your personal electronic devices all have sufficient password protection and encryption on them. And have them set to upload to the cloud at a regular interval.
7. Turn off fingerprint access to unlock your phone and delete your finger prints from the memory. Some jurisdictions allow law enforcement to compel you to unlock your phone if it has finger print based access. Or get a disposable phone just for this occasion.
8. Turn off your phone and other personal electronic devices option to connect to known wifi as it can be used as a way to fail your encryption.
9. Bring a bandana or neck gaiter and water so you can make a make shift gas mask in case things get out of hand and tear gas or pepper spray is deployed.
10. Bring a bottle of saline eye rinse in case you need to rinse your eyes out if tear gas or pepper spray is deployed.

Rest of post at link above.