Provoke when figuring it out as a new tank was a bit tricky for me at first, until I read the tooltip a little bit more. They key to Provoke is that it does not generate any enmity whatsoever. It only puts you at the top of the hate list for aggro.
If any damage is dealt to the monster before another enmity attack is used, you get placed 2nd in on the hate generated.

The best way to provoke is to follow up with another enmity attack. This will keep you at the top of the hate list. (Spinning Slash recommended)