Another thing that makes your life as a tank easier is marking, although it seems hardly anyone is doing it anymore and then they can't hold aggro.
Personally i just mark the next target with a 1, you can put the marking on your hotbar for ease of use. When the current target is at about 10% health, i mark the next target with a 1 so the DPS can prepare and know where to go next. If the DPS don't listen and attack the wrong target with non-dot single target attacks, ask them to follow the marks. If they still don't listen and pull aggro, it's their fault.
Marking makes my life easier since i know where to put most of my aggro and it makes the healers life easier since the DPS focus on a single target and monsters die faster and you get less damage. This makes it easier for the healer to got into cleric stance and deal damage too, and the whole fight is over faster. It really is a win - win situation that is hardly used nowadays because many tanks are too lazy.