Not to be construed as legal advice (which depends on your juridiction and situation and best given by a lawyer in the field), here is the way we like to approach it:
Defend reasonable Creator, human, and animal rights over all other priorities. These are permanent moral principles which may not exist in Law or the Law might be suspended. It's a choice of what you believe is right.
Find your truth based on comparison of diverse news sources, and evidence you check yourself and not trust of anyone.
Have evidence at the ready and supply it where possible. Sometimes people won't believe you without evidence but not ask for it.
Share evidence of the truth.
Only approach people as you have right to do so.
Never physically attack anyone except as necessary in minimum use of force in defense of yourself or an innocent from immediate physical threat.
Never threaten to harm anyone. It doesn't benefit your cause and only gives the other side legal ammunition against you.
Never call for violence. Even if the other side is using express (eg. weapon) or implied (eg. police-supported) violence, even if the problem you're protesting is literally violence, calling for violence (at least outside of the Law) can trigger legal mechanisms against you.
Never hate. You can be angry in the sense of enthusiastically wanting change on an issue, but to hate is to want someone's destruction and that's never good. Don't see people as the enemy but choices.
Use your right to remain silent. This is what Christ did before Pontius pilate and it would have worked if the People hadn't essentially threatened to start a riot if Christ wasn't put to death. The way our legal system works, any thing you say to police (or almost anyone else) is permitted to be used against you but is not permitted to be used to help you. But typically what you say to your lawyer is confidential.
Tend to obey police. They have tremendous physical and legal advantages and it's way less costly for them to make a mistake than you. If you defy them, usually it will not benefit your cause much but will hurt you personally for a long time. Don't approach police with a hostile or entirely uncooperative attitude. Don't get arrested for nothing. However the right to remain silent is more important than your cooperativeness with police in that you shouldn't start making any unnecessary admissions which they could potentially use against you.
Use provided channels of peaceful expression but don't rely on them. The strategy of the Establishment seems to be to control democracy at the representative level, by representatives simply ignoring your wishes however you express them.
Interact with the other side more with questions than statements of opinion. Not only are questions legally safer, while still getting the point across, but they encourage the other person to actually think rather than mindlessly defend.
Teach those who choose to listen rather than those you want to listen.
Pray as much as you can.
Prepare as much as you can.