Instance: Utgarde Keep
Box: Protection Warrior(epic gear), Resto Druid(crap gear), Arcane Mage(+- 10 epics), Elemental Shaman(+-10 epics?), Survival Hunter(a few epics).
Difficulty: easy-medium

Prince Keleseth
First clear the adds in his room. Put your group in the left or right corner at the door post that leads to his room, but put them outside that room. Put your characters in a half circle so they can all see eachother and DPS eachother when they are in an ice block.
Now aggro the boss and run back to your group. You run behind the door post so the boss doesn't see you anymore.
But a picture says it all:



Skarvald the Constructor and Dalronn the Controller
I usually bring Skarvald to low health, then kill Dalronn, then finish off Skarvald.

Ingvar the Plunderer
Spread out your team and make Ingvar face your tank and face away from your team.
Stop casting on the Dreadful/Staggering Roar. Avoid the Smash/Dark Smash (damage in cone in front of the boss where he's facing at)
Because he throws a rotating axe(AoE damage) around, you should spread out your characters about 10 yards.