1. At first you will lose. A lot.
How many matches do you think you'll lose before you start winning? Ok, take that number and add a zero or two. You're in the ballpark. Mages have a hard time in Arena a lot longer than most classes, due in large part to the fact that most of our pre-epic gear is high on spell damage and crit and intellect, and not so high on stamina. Until we've earned our first few pieces of high-stamina arena gear, we tend to die in only a few hits from just about anyone. Unless you've somehow been adopted into an already established and very good Arena team, you're in for a lot of pain. Stick it out, assemble a few pieces of gear, and this trend will start to change. I'm sorry if that sounds discouraging, but it's simply the way it is.
2. You will die almost every match.
Here's the cold truth: unless you have a healer teammate, the other team is likely going after you first. They see your mismatched blue and green cloth armor and visions of a quick kill dance through their heads. Clothies might as well have a giant bullseye painted on their heads in the Arena. The opposing team will come after you quickly, and kill you before you can say "Ice Block." Survivability is very difficult to achieve for Mages as a class, perhaps moreso than any other class. There are a few ways to extend your life a bit, though.
a. Spec Frost. No other Mage spec can survive in Arena as long as Frost Mages. Your raw damage potential may suffer by speccing this way, but you can't Pyroblast anything if you're dead. Oh how I wish you could Pyroblast things after death. I wish it so much.
b. Learn ways to "drop aggro" when the other team comes for you. There are two tools for this. One is good and the other is only good on very rare occasion. I'll go into both of them in a minute.
c. Blink. A lot. I mean all the time. When Blink's cooldown comes up, it's almost always a good idea to cast it. It's maddening for melee classes to try to follow a Mage who knows how to Blink and does it a lot. After 2.4 hits, Blink will become a lot better, so learn it and love it. Using it in conjunction with Frost Nova can sometimes buy you enough time to run behind a pillar and bandage or eat/drink. The only time I can think of when you shouldn't be blinking is when you're not being attacked. If that's the case, well, enjoy killing the other team.
d. Make friends with the healer. Make sure he knows he can heal you when you're Ice Blocked. Bake him cookies. Tell him the Warrior said something nasty about him. Do what you have to do to get him to throw you just one heal, any heal. If you can get just a few more seconds of life, the damage you can do with it is greater than almost any other class.
The trick here is learning to be as useful as possible before your inevitable demise. If you can manage to take down one member of the opposing team before you meet your painful and possibly embarrassing end, chances are you've been effective enough to help your team win. Unload your best spells, blow your cooldowns, and don't hold anything back. Unless you're very fortunate, you won't be alive long enough to save your best for last. Hit hard, and hit fast.
3. I forgot #3.
As a poster Enter points out below, I forgot #3. Wow. The lesson, as always, is I'm an idiot. This might be a good place to slip in a pointer that poster Mybones commented about: Arcane Missiles is awesome. So let's try this again:
3. Arcane Missiles is awesome.
As the only truly useful Mage spell that ignores LoS once cast, this little gem is a necessity. You may not use it much in PvE, but when that Druid pops an instant cast HoT on himself and then switches into travel form and runs behind a pillar, it's nice to know that as long as you got the spell off before he vanished, all 5 missiles will still hit him. Spec a little ways into Arcane and this beauty becomes uninterruptable. It's a bit mana intensive, but don't sleep on this spell.
4. Instant cast is king.
This is true of Arena combat in general, but even moreso when applied to Mages. Cast times are not your friend. The hunter will have his pet on you, chewing on your face, the rogue will be behind you, poking you repeatedly with sharp objects, and a 3 second cast will quickly become a 10 second cast. If you happen to be specced Frost (which, though it pains me to admit, is the way you really should be specced if you want to have the greatest chances of success in the Arena) it's easier to keep melee classes off you, and casting slower spells and channelled spells becomes more viable. Still, keep all of your instant cast spells hotkeyed, learn to use them frequently, and spec so that they are more powerful or have shorter cooldown times. While you wait for the next instant cast cooldown to end, there are plenty of things for you to be doing that don't necessarily require long cast times. During those cooldown periods are good times to worry about survival: blinking, pole-dancing, sheeping, gulping down a Mana Emerald. Re-sheep the healer, and then switch targets and blast away with your instant casts. Doing any of those things is almost always better than trying to pull off a Frostbolt with a cat and a felhound eating you alive.
5. Drop aggro
Yes, I understand that aggro is a PvE mechanic, and that threat doesn't exist in the PvP environment, but there are ways to force your opponents to stop attacking you, essentially "dropping aggro" even though aggro doesn't really apply. Did that make any sense? Yeah, it didn't make sense to me either. And I typed it! Anyway, here's what I mean. Mages have two spells that can encourage an opponent to switch targets. The first, Ice Block, is also the best. It can typically only be used once per match, so a lot of Mages try to use it like a Paladin's bubble, waiting until nearly dead before clicking it as a last ditch panic button. The problem with that strategy is that often Mages die so quickly that waiting to cast this spell can result in dying before ever being able to get it off. I submit that a better use for it is to cast it early, before death becomes imminent. Once you realize that you have 4 DoTs on you, and the Rogue has jumped out of stealth directly behind you, that might be a good time to pop your Ice Block. Suddenly you're immune to everything except heals and dispells and you stay that way for the next 8 seconds, which can be an eternity in the Arena. You've erased all of those nasty DoTs. Most importantly, you've become a much less attractive target for the people trying to stab you. When their attention has shifted to one of your teammates, pop out of the Ice Block and start firing away. You've bought yourself some time, and given yourself a small window to do what you do best, kill things from a safe distance.
The other, far less reliable method for dropping aggro is Invisibility. Because its 5-second warm up phase can be interrupted by just about anything, it can only be used when you aren't being hit. The only even semi-reliable way I've found to use it is at the start of matches, before you've been engaged. The other team is forced to either wait you out or switch their attention to one of your teammates (preferably someone more durable than yourself) giving you a few moments to reposition yourself to unleash flaming death upon them without interference. Be careful though, to time your exit from invisibility to coincide with your teammates entering the fray. If you pop out to early, they'll come for you anyway, and if you pop out too late, they've had a numbers advantage for too long. You may not be able to recover. Because you can only see your teammates, those who can see though invisibility, or those who are invisible themselves, while the effect lasts you'll have to watch your teammates closely, to see when they enter combat. When they do, it's time to pop out of Invisibility and cast away. This is especially important in 2v2, where the margin for error is smaller.
6. Gear up as quickly as possible.
Trust me, maybe the Warlock or the Paladin can survive in Arena with those quest reward blues and mismatched greens you're wearing when you hit 70, but not a Mage. You will die in horrible, horrible ways until you get better gear. You need two stats right away to be competitive in Arena, and both are hard for Mages to get from PvE drops: stamina and resilience. The quickest way to get both is in the Battlegrounds. One Alterac Valley bonus honor weekend can net you one or two very nice pieces of honor gear, and all of the season one Arena gear and the Vindicator's stuff is stacked with these two all-important stats. Arena is all about survivability, and stacking stam and resil can quickly make you a little more survivable. Is survivable a word? I say yes. Did I use it in the proper context? Shut up.
7. Don't forget about utility
You still have one of the most reliable CCs in the game, and with a relatively short cast time and no cooldown, you should be Polymorphing like crazy. before the fight begins, talk to your teammates and pick a target to kill and a target to keep sheeped. Polymorph is even fun to use as a spell interrupt if you can time it right, and then break it before too much healing can take place. Counterspell is also one of the best PvP spells in the game, especially if you've specced so that you have access to its improved version. Its cooldown is surprisingly short, so keep an eye on it and use it whenever possible. Casting the improved version on a Paladin or a Priest or a Warlock or another Mage renders them almost useless for 4 long seconds. Set up a focus macro for both spells, so that you can put the hurt on one opponent while keeping an eye on your sheep/Counterspell target. What's that? You don't know how to set up a focus macro?
8. Set up a focus macro
Focus is a neat little mechanic every Mage should know and use in both PvE and PvP. It allows a Mage to set one target as his focus (someone he wants to pay attention to but not necessarily target), and keep another as his actual DPS target. There isn't really a viable in-game interface to make use of it, so you may need an add-on. I use Focus Frames, simply because it's as simple as add-ons come, and I like to keep my interface simple. All it does is add a frame for your focus. You can place it wherever you choose on your screen, and it allows you to keep an eye on whoever you've sheeped and reapply the sheep when necessary without changing your primary target. Our own Amanda Rivera wrote a nice column on making the macro itself back in September of last year, so go read it and set one up. Trust me, you absolutely won't regret it.
9. Get the trinket.
Again, this applies to everyone who wants to PvP at all, but Mages need to know about it too. If you don't already have one, you need to get your faction's PvP trinket. These have been around forever, so they're very cheap. You can get one in just a few Battleground matches, and they will help tremendously. Because CC is such a huge part of Arena combat, and because losing control of your character for even a few seconds can kill you and your team, it's imperative to have a few options to break it. This trinket will break any CC out there once per fight usually, and the improved version can sometimes be used more than once per fight. Get it, use it, love it, and for the love of all that's holy don't forget to equip it before you hit the Arena like I always do.
10. Exploit matchups
You'll quickly learn that in the Arena, it's all about matchups. There's a reason that the 2v2 brackets are dominated by Druid/Warrior teams. That particular team has very few natural enemies. They are the top of the Arena food-chain. They match up well against most teams, and have relatively few counter-classes. On the other end of the spectrum, Mages have tons of counter-classes. Learn your limitations. Don't try to take the Warlock one on one. He will kill you, shame you, steal your girlfriend, kick your dog, and then tell your family disparaging stories about you. Avoid Rogues, unless they're attacking someone else. Look out for Priests and Druids.
On the other hand, rejoice when you see Warriors. You can kill them. Just keep them away from you as much as possible, because you are wearing a dress and swinging a stick and they are wearing plate armor with lots of spikes and things on it, and swinging a giant, barbed, two-handed meat-tenderizer. Hunters? You can kill them too. Just avoid spells with cast times and keep their pet off you. Paladins are fun too, but be careful about the timing on your spells. Whittle them down, Counterspell at the right time to prevent their bubble and burst damage them back to meet their maker.
We have many weaknesses; mainly, we are ridiculously easy to kill. But we also have certain strengths, and learning to minimize our killability and maximize our killometry can make Arenas a rewarding experience for us. Yes I know I just made up two more words. I like them. Don't complain. I don't come to your house and complain when you make up words.
Arcane Brilliance will return next week with what will hopefully be a Magetacular celebration of all things 2.4, assuming the patch hits Tuesday. If it doesn't, well, I'll think of something.