Lord Jaraxxus - (Heroic) Trial of the Grand Crusader

While seemingly similar to normal mode, there are a few subtle yet SOUL DESTROYING changes to this fight to make it hard(ish)

Shopping list:
2-3 tanks
6 healer (at least one pally to make it easy)
good mix of DPS

So, NER, Is this the same as normal?
The basics yeah. Go read up about tanking and all that jazz in my normal mode description. You can find to the right there.

So everyone spreads out evenly around the boss because...

Stuff that is different will kill you.
(Note, all link numbers are for reference of the spell only. Consider the damage dealt to be like 1000x bigger than listed! cos this stuff is LETHAL)

Portals
Portals are now bosses that you need to kill. The longer the portal stays up, the more mistresses of pain may appear out of a portal. You need to make sure that everyone, and I mean everyone, switches to the portal. Infact, any boss timer will tell you when the next portal is due, so you have no excuse not to shift, move do whatever you need to do to be ready to SMACK THE CRAP out of that portals. Having 2 mistresses out will tax your raid too much to possibly complete the encounter, so getting that portal down before the second mistress emerges is a must. Everything else is business as usual.

Mistress' Kiss.
As pointed out by a very helpful reader, I completely forgot to address this. The mistresses will cast this debuff on you randomly. You can tell because you will have love hearts streaming out the top of your head (the same as the skunk pet when it is chasing the black cat pet! SO funny... but anyway). Now, for most melee this isn't an issue, just ignore it. For spellcasters, it has an interrupt effect on your next cast. There are a couple of ways to deal with it. Cast instants. Cast a nonuseful school of magic to take off the effect and interrupt a tree you don't use so much. Or, if you are like me and a holy paladin healing your little butt off, you need a way to deal with it. Here's the skinny. Use Aura mastery and keep going. If you don't have that then just cast something. The 8s interrupt is shorter than the 10s duration of the debuff. Triggering it gets you back into the healing game faster than waiting the 10s.

Volcanoes
Differences here is that, again, the volcano is DPSable and needs to be destroyed before 4 elementals appear and rip your face off. You can probably keep going with 4 up, but it will tax your raid pretty hard. The one thing you really need to know about these elementals is that they are no longer banishable. Not once, not at all. IMMUNE BABY! Tank and spank them as best you can. Stay on your toes as 2 ticks of the fire on you will kill you dead, dead, dead. Pre-empt them as much as you can. Staying alive is your priority in this section.

Legion flame is lethal.
You cannot stand in it, you cannot track it into anyone else or you will die, guaranteed. The trick to this is everyone evenly spreads out around the boss. If you get legion flame you mouse turn away and run toward the back wall, and once you are out of the way, turn in a little circle and head back toward the boss. This should keep you in range of heals (cos if you get out of range, again, you WILL DIE)

Interrupting and spell stealing/purging will mean you wont die!
Get an interrupt rotation organised and make sure that you never miss a single one or the raid will wipe. Never let the buff stack on the boss get beyond 5 (yes, I know it starts at 10, get it down ASAP!) or the chain lightning will snap people dead. If that means your one mage does nothing else other than decurse and assist with interrupts then that's what you need to do.

Incinerate flesh.
Not healing this will wipe the raid. No Joke. I should add that we call the heal target and then we call as SOON as our heals become anything other than "absorbed". Use a good scrolling combat text to ensure you are aware when to stop healing and get back onto everyone else.

Anything else?
Yeah, actually there is.

And that is how you use your CDs and heroism/bloodlust.
First portal - blow CDs
Volcano - go as hard as you can to get it down
Second portal - blow heroism
Volcano - go hard
Third portal - blow CDs
Volcano - go hard, if jaraxxus is low in health, it could be worth ignoring the adds and going hard on him instead, but that is a judgement call at the time.
Fourth portal - Boss should be VERY NEARLY DEAD at this point, but even if the boss is at 5% you need to swap to the portal and close it as fast as possible, then ignore the adds and get the boss.

I think that is about everything. The basics of the fight are pretty much the same, its just that anything you could heal through in normal is deadly in heroic.

The key to this fight is getting it right and not screwing up. Much like Hardmode XT. Goodluck!