Lick King AoE grinding guide is here. We are now to speak of this in depth, it is important for those who sick of questing or only level 70. If you are a Mage, this is not to understand. At that moment, it is the time for us to look at it in detail.
   For AoE grinding, the most important stats are Stamina, Intellect, Spell Power, and Critical Strike Rating. Stamina and Intellect are important for staying alive long enough to cast your blizzard spells, and to make sure that you don't run out of mana in the middle of a pull. Spell power increases (albeit slightly) the damage done by blizzard. Not as important as the other stats, but it's very good to have. Besides, most quest reward gear gives adequate amounts of spellpower anyways. Critical Strike Rating is good too, now that blizzard can crit.
   There're two items in game for Trinkets like The Lightning Capacitor and Thunder Capacitor. The former drops from Illhoof in Karazhan. Alliance-side, the latter is a quest reward from a quest chain in Dragonblight given by the NPC Zivlix, located at 54, 23, just north of Galakron's rest.
   In particular, those two trinkets are that they have stacking effects. Each tick the crits will add a charge to both items. Since Blizzard is going to crit, you're going to have charges proccing left and right, dealing a whole ton of damage in the meantime. Testing naked on 6 theramore combat dummies, the two capacitors alone increased DPS by about 800, compared to using the badge trinket and its brewfest equivalent.
   Due to the new features in 3.0, it's easier to take down multiple mobs such as Blizzard critting, as well as Shattered Barrier. You can follow the easy steps are below.
   One is to cast Ice Barrier, you can wait for the cooldown to run down a bit.
Then you run around and gather some mobs. Make sure to just get into their aggro radius, rather than walking right into them, to minimize their damage done to you.
When Ice Barrier's cooldown is up, cast it again as you wait for the mobs to gather around you. Let the mobs pound on you until Ice Barrier breaks. Shattered Barrier will freeze all the mobs in on space. As soon as it breaks, blink away at once. Make sure you blink to a spot that's not close to another mob.
Thanks to the snaring talents, you are able to fit up to 3 Blizzards before they reach you. With adequate gear, you should be able to kill them before they reach you as well. If not, then Frost Nova, Blink, repeat
Some of the best mobs can be AoE'd do not have an aggro radius at all, and will only attack if they are provoked by an attacker. These exist mainly in the form of animals scattered around the place. You can find some that noticeably travel together in formation, thus they can be AoE'd at once, without having to lure each to a particular spot.
However, there's a "bull" version of that mob that does have an aggro radius, so it's wise to grab that one and lure it to the rest of the pack. Once you meet up with the rest of the pack, use Arcane Explosion to aggro the entire group and continue with the grind, either by Shattered Barrier or Frost Nova.
Just remember this method works ideally when you gather a group of mobs that are purely melee-class. You don't want to be pulling any ranged classes or casters. Sometimes there are mobs that charge after aggroing, which completely disrupts the pulling process.