Water Elemental Basics

Random Thoughts on WE:

Double up on stopcasting bind. It is pretty reasonable to macro this to be:
/stopcasting
/petpassive

This ends up being versatile in a lot of situations and it is pretty rare you want to do one and not the other. Basically becomes, a stop button for everything you're doing. (Say your rogue teammate lands a blind on your pet's target)

Bind petattack to something intelligent and don't use scrubby pet assist macros. WE does a lot of dmg, it is great for secondary damage in arena if you run staggered or split DPS. You should be comfortable at switching targets with WE as if you were simply tab-target fireblasting to assist the DPS train. A lot of people just summon their WE on the target their team is nuking and leave it autoattacking a target getting spam healed all game; without getting into if this is good or bad (it does keep moderate healing pressure up), realize at least when you switch targets you're leaving a good chunk of DPS behind if you don't control your WE well.

You should pet nova with about .5 + your latency seconds before your frostbolt finishes to bolt->lance combo off the pet nova. A LOT of people nova sooner than necessary and I watch nova gets dispelled before they get off their lance. (The bolt will still get shatter bonus even if the dispel occurs midair, shatter is calculated when the bolt leaves your hand) This comes up not very often against casters since they often have multiple debuffs or are on global, but against rogues, who have many ways of escaping nova, gnomes, or druids, you should try to be reasonably "tight" on the window you give them to escape the nova. It is a pretty big damage loss if you don't get the shatter bonus on both.

You need to be at 8 yds or more to shatter combo reliably. Why do people try this on people literally on top of them?

At 25+ yds, you can get shatter bonus on all three spells: frostbolt, ice lance, and fireblast. This is of course easier with gladiator gloves. I've heard you can get this even at much shorter distances, and I haven't really confirmed it either way, the point is that distance is your friend when pet nova comboing.

Be wary of Psychic Scream or Affliction Howl of Terror. Some teams will save this stuff for pet summon, there isn't necessarily a ton you can do, but stall on summoning pet until you can be well spaced. You both eating the fear is pretty bad news for your team.

WE obviously benefits a good deal from activation trinkets, you of course should be using them when you are confident you can land a good pet nova combo. A lot of people go for their WE burst, see the target doesn't die, and then pop trinkets and just try to chaincast (perhaps with heroism), recognize that you lost a few hundred potential burst damage by not using it sooner.

Do not rely on the AI to avoid CC'd targets. This is pretty obvious, when you poly, switch your pet target manually, if your pet is midcast, its not horrible to use the aforementioned stopcasting bind as you change targets, the split second doing this is better than repolying and wasting 6 seconds of potential poly to DR.

Don't kill other mages WE. If you're a WE mage, you of course realize that your pet is a lot of your damage, and are more likely to advocate killing opposing mage Water Elementals. If you're 17/0/44, you are horrible at doing this, and you could spend time doing better things. Your teammates are MUCH better suited to killing a frost immune target than you. You can finish them off or help out a bit with a fireblast, but don't sit there scorching or missiling or blasting or whatever.

Save your own frost nova for defensive purposes and use the pet's nova for shatter combos. Good shatter combos are not much weaker than AP Pom Pyro+Fireblasts, but you can do it 4 times, while they get to do it once. Thinking of your pet nova as your "pom pyro" equivalent is important or you are not a burst damage threat. Moreover, it is extremely rare you'll get to use your own nova and frostbolt someone in arena, more often than not, you're just getting an Ice Lnace off that nova, why not save your teammates with it instead?

Just because you have your pet out does not mean you let your pet do your damage while you spam CC and poly juggle. AP Frost is better suited to playing this way, you want to find opportunities to draw fire or outright cast bolts on people. CC when you can, but you are there to deal damage, and you should be threat if you're left unguarded to openly cast. I don't like to switch to hardcore CC until after the first kill, because it really gives up sente. By the way, you should never cast non-rank 1 poly.