Since I'm personally still catching up to the rest of WoW, I'm just going to post some basic stuff here re: mageing in Draenor. Here's what I've found works and what doesn't, along with the best(?) options for first-tier raiding.
Frost is the go-to spec for leveling, heroics, and intro raiding, for two major reasons: 1) you have much better CC and damage mitigation options--your pet and your armor--to help you level without dying; and 2) it requires far less Mastery than its counterpart (Arcane) in order to do well on DPS, instead relying on Multistrike.
In short, Frost is better survivability with more-than-decent damage output, and is the best starting choice for intro raiding. It's also used at later raiding tiers interchangeably with Arcane given you have enough gear to manage both specs. Frost will do better on AoE in general.
Your primary stat for any spec is INTELLECT. Following Intellect, the best stat you can take for Frost is Multistrike.
Haste, Crit, and Mastery are about equally on par for "third best" with Versatility being unimportant to you.
I personally run with Ice Nova (t5), Mirror Image (t6), and Prismatic Crystal (t7).
Since others have done it much better than I could for the purposes of this post, SEE BELOW for detailed information on the Frost Mage and its rotation.
Frost is also more viable in battlegrounds given the immense number of freezes, slows, etc. you can dish out. I'm no PvP expert (ask Jety), but I can tell you people HATE your Ring of Frost. If you're speccing for PvP, you'll want to pay more attention to Versatility.
Arcane is currently the top-performing mage raiding spec, but is also harder to get decent output from if you don't have the gear and talents for it. Arcane relies upon Mastery first and foremost after Intellect, and Mastery gear is harder to come by at the lower ilvls.
For leveling, Arcane is certainly possible, but a difficult choice given that you'll be less able to CC (without use of the elemental's freeze, for example) and more dependent upon hitting hard and fast - and focusing on SOLO kills rather than AoE. Your survivability should be decent so long as you're using Ice Barrier whenever able, but you're still more squishy than a Frost mage.
The same will apply in heroic and raiding situations: your single-target damage should be exceptional, with AoE being far less so.
Arcane is reliant upon a steady conserve/burn phase rotation. The idea is to build Arcane Charges with AB, use Evocation, and then enter "conserve" phase (using your t5 and t7 talents for far increased damage and lesser mana cost). Contrary to how you think it should work, your "burn" is NOT your major damage output phase. It's just a Charge builder. Your real damage will hit with your Nether Tempest or Supernova casts (below) - and this is why Mastery is needed. You'll be casting your NT or SN with as close to 100% mana and as many Arcane Charges as possible, and Mastery: Mana Adept makes it so that you'll be hitting for a multiplier of your damage output based upon the amount of Mastery you have.
INTELLECT first and foremost. Your next most important stat is Mastery, due to the Mastery: Mana Adept passive skill you earn upon selecting Arcane as your spec. Following Mastery, Haste/Crit/Multistrike share third place, with Versatility again coming in last.
I've currently chosen Nether Tempest (t5), but Supernova is a viable option here as well and arguably better for burst damage where NT is more sustained. Rune of Power (t6) will be the best choice for you, as well as Arcane Orb (t7) if you're using NT, since Orb will build stacks of Arcane Charge. If you chose Supernova at t5, you'll want Prismatic Crystal at t7.
*NOTE if you know you'll be in a fight where you'll need a lot of burst damage, Supernova/PC is the better combination.
Much more on this spec here:
Having only barely touched Arcane in PvP, I can't speak much on this area aside from the initial "it's not as good as Frost" reaction. However, there's information below on how to do it:
Interestingly (and not too surprisingly), HASTE outweighs everything else here, even Intellect.
Hope this information helps you on your way to mageness!