Hi folks,
I've found a little trick on my mage.
As you know, the water elemental has two abilities: a nova and a water jet.
Those abilities have a shared cooldown so you have to choose if you use the nova or the waterjet.
You can also (and many mages do that) lock the waterjet and the elemental will cast it on cd, as soon as available.
The trick is very simple: there is always 1 sec before the automatic waterjet casting, and that's exactly the moment you have to take to clic (or bind, it's even faster) and use the nova. Just after the use of the nova, the water elemental will cast the locked water jet as planned.
Congratulation, you just bypassed a shared cooldown