Next one I will take will be Exploration.
I will not explain how to explore every place, that you will have to do yourself.
First you will need to download a addon called _Npcscan, one of the best addons ever.
Because almost everyone got this achievement and nobody is in Outlands anymore theres barly any competition.
The Northrend might be a bit harder, but not a big same as Outlands one, there is not many left in Northrend, but you need luck, and probobly will have to go up early or stay up late to check for them.
Purely luck based... If someone in the guild gets it, you might have a chance of geting it by using some sort of teleportation, but most likly not. Or you can just wipe on Deathwing when he is released.
This is a sloooow and boring fight, just download RangeDisplay and let someone that can kite do it, kiter needs to be inbetween 8-20 yards from the shark not to get out of range, its pretty easy with even just a few people, dont pull aggro, it will oneshot and reset .