Just marvel at how it could be that we're fine one moment, and some combination of words or events or thoughts come about, and then we could be furious before we know it. Isn't that incredible? It means that this isn't a problem of knowledge. We already know we don't want to be angry, and that hasn't helped us much. Anger is an attention problem, not a knowledge problem.
Why are you not furious right now? Think about something that has made you very angry before right now, just as an experiment. You can bring anything to mind if you wish, right? If you wanted to picture a... cup of tea, you could close your eyes and do that, if you wanted. Try bringing to mind a thing that made you very angry and just reflect on the story for a few seconds. See if you can close your eyes and do that right now, just a few seconds.
Okay, well assuming you're back-- why aren't you enraged right now like you were then? The facts of "the thing" are still there, but the crucial variable that's missing is you are just not hypnotized by these facts. They don't grab you by their teeth like a dog with a chew toy. You're not at their mercy , and your mind is more clear to reflect. That's exactly the property of mind that frees you from anger in the peak of intense anger. All of this is just explanation, and ultimately you'll have to exercise this property to get better and better at it. Again no amount of knowledge or words or concepts solves this. Any time you're a little angry, just realize you're angry, and pay full attention to that anger and see what happens. Make a commitment to stare at it and not react to it or judge it or try to make it go away. Only observe with total acceptance, and notice the results like a scientist would. "Hmm, what is the character of this anger? What is its signature in the mind, in the body?" "How does it change, if observed?" "Does it get worse? Does it reduce? Stay the same? Go away?" "What is the attitude about these things?" Just notice.
These are only examples, you don't have to ask exactly that, the general idea is to just notice and be curious however is comfortable for you, but not get lost in the story("The *reason* I'm mad is well because it's just so unfair how <blah blah blah blah> <--- this is not what we're doing, since that is the exact hypnosis that fuels anger. We're observing this instead, as a thought"). No need to force it, by the way. It can be helpful to sit down and do this with eyes closed, after some deep breaths.
no promises on my suggestions but
