Hi Mia,
I definitely don't know how to fight back.
 I know how to save my life--I run!
I worked once in a situation that included a coven of religiously-inclined conservatives and a couple of  narcissists (fully-blown) .  I worked there for far too long and it nearly did me in.
I think I stayed because I thought that reason would prevail.
Not always, I discovered.
And I headed for the hills, barely escaping with my wits about me.

You have to know when to fold'em sometimes

What a difficult question Mia!

First, I'll link to some connected discussions, which you know about but for other readers:
On Strategy
Bar Fights and the male psyche

How to fight? Perhaps we should start by asking, should you fight?

In the topic of Upgrading yourself, Edna says in post: "Your post resonates with my idea that struggle is necessary in appreciating what we have. One of the reasons I like trying different instruments, including ancient ones, is that it makes me face difficulties which I must overcome. Through the process of overcoming them I will learn something new that I didn't notice before in the music. It's as if the obstacle frees something inside and permits a new gaze."
 
Let's take the example of Mathematics. One struggles to solve a problem. Should this struggle be considered a fight? I don't think it does for the great mathematicians. It's definitely a struggle, but the ones who try to impose their will on the world have limited success.
It might seem to you that the people you mention like to fight, but perhaps they don't experience it as fighting but as jousting (which if you look at the dictionary is somewhat synonymous to fighting), as a certain obstacle to overcome. Is jousting really fighting?
See also related discussion on How to win.
Some people see arguments as simply a fight. They argue their point and enjoy the battle. These are never interesting arguments, as you want to talk with people who might joust with you, might use your counter-force to improve themselves, but are also always listening, always open to the truth, and never try to impose their will on the outcome. It's not always easy to distinguish the two.

Moreover, fighting isn't for everyone. Some people like it and some people don't, and if you're one of the ones who don't you shouldn't try to force yourself to fight as it is definitely not the only way to advance, it is simply a way. A way which might not fit you and in fact my poison you. A way which, for most people, leads nowhere.


Now, on to how to fight. That's a tough one. For people who like jousting one learns how to fight from everything one does. Example: when I play Pacman I learn how to fight. In life many time one wants something, it seems at hand, and the desire makes you blind to the goings on which will impede you from getting what you want. Pacman constantly forces you to change your plans. You think you can almost make it, but you learn to change course and operate differently. It is quite an educational game as it doesn't only tell you how to behave, it teaches you and makes you understand how to behave.
Obviously from playing chess you learn how to fight.

Other possibilities are reading books. The classic ones being Clausewitz On War and Sun Tzu's The Art of War. Also, Machiavelli.
But if you go on to read any of those, read them with the purpose of learning to joust and not to fight. Fighting is much less interesting.