Hello! So I seem to have a lot of luck with Shadow and Water pets as tanks (at lower levels), but not so much with Earth. I'm wondering if I'm doing my proficiencies wrong, as the gear is pretty straight forward.

So what do people put their proficiency points into?

Also, what's your rotation? As in, do you keep the Thorncoat up whenever it's available, only for when you know the mob i going to hit hard...etc.

With a level 65 earth tank, I have one point each in health and strength, and two in agility. I bring Thorncoat up whenever I notice that it's refreshed (which I personally don't pay much attention to), and when I have the mana to use it.
Might not be the most helpful advising, but she's served me pretty well. I'm sure that with a max stat, you'd have much more health and overall power with such a setup.