There are countless threads nowadays in our boards asking for advice as to how to raid with arcane and after posting in 3-4 of them and see a couple others being created, I've decided to try and help out as much as I can so all the questions can be summarised in one post. I'll either type it or paste stuff that I've myself written on other threads. Here goes! :)

-Advantages of being arcane:

Your hit needs are far lesser than that of a fire/ttw or frostfire build. That leaves you room to gear for more haste/crit with ease.

Controllable burst: unlike fire-based builds whose burst is random and based on crits/procs an arcane mage will decide when and how he wants that burst applied. It's the one advantage you have to exploit if you want to push competitive numbers.

No threat worries whatsoever - unless the tank dies or it's a threat sensitive fight with threat resets, it's nearly impossible to pull threat as arcane with a good tank, unlike fire builds.

Reactive playstyle: unlike fire builds whose rotation is a priority system arcane mages can tweak their rotation according to how much mana they can afford and how much HP their target has.

-Disadvantages of being arcane:

Mana, mana, mana. The blue bar will always be the first of your concerns. Unlike fire, you will have to use evocate at least once on every bossfight. If you can't guarantee a safe one your dps will go down. Replenishment is a must to keep up with heavy mana rotations and so is having a decent spirit rate.

No utility whatsoever. Leaving intellect/tables/focus magic aside arcane mages don't even bring crit buff so if it's utility what you are after you may consider other builds.

AoE capacity. Although fire/ttw isn't a great build either in this sense, the main AoEing spell arcane has requires you to get close to the target which can be both frustrating and dangerous. You will find yourself using frost/fire spells when AoE is needed.

-Build:

This is the build I'm using: http://www.wowhead.com/?talent#ofoVcu0IzxGuMxedcZbhf0o:Nzwo0m

Explanation: Bear into mind, arcane talent tree is pretty bloated at the moment so while there's a few "must" talents that every mage will pick - torment the weak, missile barrage, etc - there's not enough points to pick everything that could possibly improve your raiding. For instance, I've left Arcane Stability out of my builds because during raids I'm hardly in a situation where I'm missing it. I've also left Magic Attunement out because I find range isn't a concern at all except for some situations.

But you have to understand these were my personal choices. If for example you find increased range a necessity then by all means go for it, so long as you don't drop any fundamental talent!

I would add as tip to use the filling points in frost tree and spec Frost Warding instead of Ice Shards. What would you prefer as arcane, higher crits on blizzard AoE or a 30% chance to negate a fire/frost based damage spell and restore as much mana as that spell would've caused? In fights such as Ignis, Hodir, Mimiron, Razorscale, it's an invaluable talent... Pop it before Ignis uses Flame Jets and watch how you absorb all the damage and regen 5k-6k mana for free!


-Glyphs:

I like to say there's two glyph setups for arcane according to how offensive mana-wise the mage wishes to go. It's a question of personal preference in my eyes, here goes:

Offensive mana using setup: You use Arcane Missiles, Arcane Blast and Molten Armor glyphs. You use Molten Armor during bossfights. Your efficiency will be a tad worse but your crit rate a lot higher, needs good gear to sustain heavy mana rotations with this setup.

Efficient mana using setup: You use Arcane Missiles, Arcane Blast and Mana Gem glyphs. You use Mage Armor during bossfights. This is the one I use because to me the more mana, the further I can push Arc.Blast during nuking phases. Along with t7.5 x 2 setbonus, I'm getting up to 6k+ mana per gem.

Now you are probably wondering, which setup should I choose? I can tell you, I know mages of either type and they all push more than competitive numbers. Option a) (Molten Armor) is said to be relatively higher dps-wise but as with talent build, it's also a question of personal preference. Thanks to using the "efficient" mana setup I run with 650+ mp5 in combat with raidbuffs and trust me I can push that Arc.Blast key for quite a while during nuking phases!


-Gearing:

These are the steps I usually follow when gearing up as arcane:

Getting hitcapped: 11% off gear without raidbuffs, 8% with raidbuffs and even 7% if there's a draenei in your team, if the balance druid/spriest dies tho I'd have a weapon with hit ready - I use a staff from Freya 10 man - to be equipped as losing 3% hit midfight will mean dps will go down.

Here comes the hard part: have to balance your gear so you have high spellpower, high haste - haste > crit for arcane - decent spirit rate all while keeping a decent crit rate. (I aim for around 20% crit unbuffed) Luckily for us arcane mages there are plenty of items with high spellpower, haste and spirit - for instance, check Lifespark Visage off Flame Leviathan - Ulduar 10 man. That kind of item is brilliant for us.

So a quick recap: hitcapped > spellpower / haste > crit all while keeping a decent spirit rate.


-Gems:

These are the ones I normally use:

Red: Runed Scarlet Ruby (19 spellpower)

Yellow: Reckless Monarch Topaz (9 spellpower - 8 haste)

Blue: Purified Twilight Opal (9 spellpower - 8 spirit) - although you could also use a Glowing Twilight Opal (9 spellpower - 12 stamina)

Meta: Chaotic Skyflare Diamond (21 crit rating and 3% dmg increase in crits) - been theorycrafted to death and this is by far the best meta for mages regardless of spec.

-Rotation:

This one is a bit tricky, and not always easy to answer. Arcane rotation relies on your mana so the more efficient you are, the higher your dps will be. The general rule I use during raids, however, is:

During a normal phase: Arc.Blast x3 --> AM if there was a Missile barrage proc OR Arc.Barrage if there was no proc. (I will explain why a bit below!)

During a nuking phase - XTT heart is exposed, Razorscale is shackled to the ground, Yoggie p2 when ranged goes to crusher tentacles, etc - pop cooldowns and spam Arc.Blast until 70%ish mana, pop gem and then carry on using Arc.Blast nonstop until cooldowns wear off / nuking phase is over. By that time you'll most likely have a Missile Barrage proc so unleash the charges and get back to the normal rotation

During specially bad circumstances - replenisher dies, you die, get bressed and lose raidbuffs, you mess up with your evocation - you can shift down to a lower mana rotation and stack A.Blast just once or twice before unleashing the charges.

-Do I release the Arc.Blast charges with AM or Arc.Barrage?:

If Missile Barrage procs, there's no question, AM all the way!

If there's no Missile Barrage proc then it's not so simple. ABx3--> Barrage pushes slightly more dps than ABx3--> AM without proc. The advantage of using ABx3 --> AM regardless of missile barrage proc is it's better DPM-wise and that's why many mages defend it, because mana is arcane's game. However, when there's no missile barrage proc using ABx3--> Barrage isn't a bad idea at all if you have the mana to sustain it

I'm seeing Arcane Barrage regular 13k crits on normal fights - not Hodir or Yogg-Saron, etc where you get damage boosts - when 3 A.Blast charges are up and with procs etc I've found a 15.5k crit on Freya, not shabby at all for an instant! Also, using Arcane Barrage instead of AM when there's no proc allows for more flexibility in movement fights. Non-hasted AM go far too slow and often you would have to move before the channelling is over where as if you finish your rotation with an Arc.Barrage the GCD after it allows you to step out of the "fire-on-the-ground" losing minimal dps time.


-Evocation: the blue "whoosh!" and you:

Evocating safely is a must to push numbers as arcane. Actually - contrary to what people say about arcane being bad in long fights - if you can evocate when needed you can keep a heavy mana rotation forever. Generally speaking what you should do is learning boss abilities - i.e. the ones who will ruin your evo - and time evocation accordingly.

For instance, wait for Ignis to cast Flame Jets before using it, or when doing Sarth with drakes up wait until the drakes have spawned their voidzone somewhere before popping evo - so it doesn't spawn ontop of your sorry mage arse while you are evocating.

It usually helps to have a discipline priest shield you before you evocate in high damage fights and I have a whispering macro ready for that. Not only do those bubbles absorb up to 6k-7k with raidbuffs but they get mana back when casting them thanks to Rapture talent.

Another tip - thanks Cinondra - is profiting of casting speed buffs - icy veins, heroism/bloodlust, procs from trinkets - to evocate even quicker to reduce the chance to have it interrupted. As a rule try to use the last second of such procs so you squeeze the most dps out of it.


That was it, hope it helped, good luck for all the arcane-heads out there. :)