yvkdreamer, there's nothing that can be done to calm down someone else. But if that person decides to do so, they can work to bring themselves under control. I know this first-hand. It took a personal epiphany for the right perspective to work on myself. I purchased a stack of anger management books and studied. I found techniques which worked for me.
Now, to get on topic with the forum: Meditation did help, but not in ways that a lot of advice suggested.
Many sources claimed that meditation alone, mindfulness meditation or simply clearing one's head, would improve temper. That did not work for me. However, I used visualizations, mantras (many which I made myself), breathing techniques, energy manipulation (I didn't know about grounding and centering as such before I came here, but it made sense because I was already doing something similar), and other similar things to let go before I blew up, or to bring myself back quickly if I went over the line.
But it all comes down to the person making the decision to change. Nobody else could change me. I had to do the work myself.