I'd read up on the strats on bosses at Wowwiki.com, knowing the fights is a major part of being successful.  

Also I'd make sure you have plenty of pots, stamina food and elixirs if you can, just to make sure you're the best you can be.

Make sure you're gear is all enchanted/gem'd out, even if you dont think it's a great piece.

Make sure you're rocking a threat meater like Omen, and Deadly Boss Mods.

Finally, I dunno how much you have tanked, but make sure you're comfortable being a tank by doing 5 man instances and such.  Tanking isn't something you can just throw points into protection and, slap on a shield and do.

Browse around these forums, Dreadwind has dropped tanking knowledge on us multiple times and even if you do know alot about tanking you can can still learn something!

Good luck! Hope to see you there!