Mages aren't the easiest class to level in WoW and are generally respected for their abilities in PvP scenarios. Some would argue that the Mage is one of the more difficult classes to level in WoW although this isn't strictly true they just require a bit more skill to master.
The Mage class are equipped with some nice abilities for solo leveling including the ability to teleport between continents which is a huge time saver and the ability to blink which reduces running time as well as enables the Mage to evade danger.
One of the more common problems you'll face when leveling a Mage is which talents to assign and which Mage talent build to follow. There are three build types you can pursue when playing the Mage and they are Fire Mage, Arcane Mage and the Frost Mage builds.
Each build has their advantages for instance, Many players like the Frost Mage talent build as it is more mana efficient and a more steady build than that of say the Fire Mage talent build which is a bit more dangerous and unpredictable and can leave the Mage vulnerable to attack and drains a lot of mana but at the same the Fire build has a very high DPS (damage output) and is therefore favored by players looking to get involved in PvP realms and battlegrounds.
The most popular build for leveling is the Fire/ Arcane Mage hybrid talent build which offers high DPS and leaves the Mage less vulnerable in attack. This build still isn't as steady as the Frost equivalents but offers a decent talent leveling build and is suited for other instances in the game.
Fire Mage Talent Build
The Fire Mage talent build is quite predictable with many opting for the fireball - fireball - fireblast combo during combat which will more often than not will eliminate the enemy. Later into the talent build the Mage will unlock the Dragon Breath ability which really is a deadly talent to throw into the build.
The Fire Mage talent build primarily relies on high DPS and will require that the Mage deals out damage before to many health-points are lost as the Fire Mage's defense is lacking!
Favored by many for PvP due to the devastating damage output this talent tree has to offer although can make leveling your Mage a little more tricky.
Fire/ Arcane Mage Talent Build
This has to be the best spec in my opinion for leveling the Mage, some would disagree and argue the Frost is the better spec but with the right approach and build the Fire/ Arcane Mage talent build can prove to be effective for solo play and group play in World of Warcraft.
With this build you'll notice that your mana efficiency is greatly improved to that of the Fire talent build making leveling easier and smoother. The Mage can also benefit from improved intellect and spirit following the Arcane talent build which is another added benefit for leveling.
The main focus here will still be the fireball spells and pyroblasts during combat although improved AoE casting spells can be acquired with this build which is nice for group scenarios.