It's one thing giving useful ideas, but never easy to put them into practice. And all children are different, so what works with one would never work with another. All I can say is what worked (up to a point) with my angry one.
@weekwhat, I'm sorry you're going through it too. My DS still has it in him to explode: he has been stuck at home for the past year, give or take, rather than being at university. So I have still seen signs of it (in fact, he started veering off down the 'angry' route last week. He was actually in the wrong about something, but I resisted the urge to remind him of this and changed the subject to something completely banal. He simmered back down. I did then bring up the original subject later, when he was in a different frame of mind).
To some extent, he has grown out of it. He's done a lot of reading (he reads incessantly), including loads about personality/psychology, which he says have helped him to identify unhelpful patterns in his own behaviour. However, he has also been fortunate in that his school has been really, really helpful. He has normally held it all together at school, but school has taken it seriously when I've explained the situation at home and have asked for help.
A PP has also mentioned trying to predict what might cause an explosion, and warding it off before it gets to that stage. I used to do that, too, but it's bloody exhausting.
The other thing which makes a difference is that being hungry has made his angry tendencies very, very much worse. That was clear when he was a tiny toddler. Even now, he is thunderous when he's hungry - but he does recognise that this is a trigger, and his cue to eat something!