Well it matters for what content.

Basics: The threat meter is located on the party bar right underneath the class symbol. As someone fill it up, they are closer to taking agro.
Hate combo chain is Heavy Swing, Skull Sunder, Butcher's block. Your main buff como is heavy swing, maim, storms eye. Depending on where agro list is sitting 3 hate combo's, buff combo
Groups, use Over Power, and keep em grouped up. After 2-3 overpowers, use the combo's mixing in overpower between the combos.
With lots of mobs, make sure you use your defensive cd's.