1. Fire

In this section we will talk about the most powerful spec of mage in the Wrath of The Lich King expansion, specifically in the 3.3.5a patch.

First of all, your are a mage, so your role is to dps, and in order to do it you need to stay alive. Mages have huge DPS potential, but they are one of the most squishy characters in the raid.

Let's talk about the Fire mage especially:

As a fire mage, you have very high mobility, and very long range on your abilities.

On the other side, you have a very long spell casting time.

So your point will be to use that time window when your brain is doing nothing but waiting for the end of the cast to anticipate movements of the boss and your mates.

If you use both this long time where your brain is available to anticipate, and your high mobility, you will be able to deliver one of the most insane DPS of the whole game. And you will be one step ahead of the boss at all times, so you will never die.

If you have a powerful enough group, these will be the selfish rules you will have to apply to increase your DPS even more:

Holding threat on the boss is the job of your tanks.

Keeping you alive on little damage such as puddles (the time you need to move without losing dps) is partly your healers' job.

But remember that if you apply these selfish rules it's your job to do amazing DPS and an ultra reactive switch on targets that need to be killed!