I try to keep two things in mind:
(1) Political attention is a precious resource, when you get it, use it wisely. That means you should ask yourself, before saying anything or taking any action, "What am I trying to accomplish by doing this and is it worth the trouble to accomplish it?" Venting feels good, but does it actually help? If not, then do the venting with your close friends and family, but leave it out of the public debate.
(2) You are being watched. You are being watched, not just by those who agree with you, but also by those who do not. And among those who disagree with you are people who truly are your enemies. As such, they are looking for any advantage they can get from disagreements you have with those who are your allies. Don't think for a moment that political operatives aren't following public discussions closely, looking for some avenue of attack to use against you. If they can find a wedge issue that will divide you from your allies, all the better. If they can find a sound bite that will isolate you, even better. (Many of the worst talking points against Democrats came from other Democrats.)
Express your frustrations. Demand justice and what is right. But do it smartly and never offend anyone unnecessarily.