So here's a little bit of a heads up once you hit 50 and start doing hard mode Ifrit.
You will either be playing the role of stunner or tank in this fight. Tanking is standard fare - it's just like tanking in a dungeon. The only thing you need to worry about is making sure your back is to the wall of fire directly behind Ifrit. You want to keep Ifrit in the same spot for the entire fight. So when you dodge his attacks, move back to where you were immediately after.
There's not a whole lot else to tanking Ifrit in hard mode.
Now, if you're asked to be a stunner then be prepared to pay very close attention to Ifrit's casting bar. He will cast two different spells. One is Eruption is another is Plume (Sorry, can't remember the full name of the spell).
Eruption is the important ability here. You need to Shield Bash Ifrit every time he starts casting Eruption. If you don't, your party will take a lot of damage and it may cost you the fight. I highly recommend NOT using any other abilities besides Shield Bash if you are asked to be the stunner. You might be able to work a couple attacks in between Eruptions but to be safe, just auto attack and do Shield Bash when he casts Eruption.
If you see the Plume casting bar appear, simply ignore it and get ready to dodge the attack. You DO NOT want to shield bash this attack because it'll raise Ifrit's resists to stun.
So simply put: If you're stunning, make sure you shield bash Eruption and ignore the Plume attacks.
Hope this info helps!
Edited, Sep 15th 2013 11:38pm by Zicash