World of Warcraft Leveling Technique

World of Warcraft leveling can be complicating but if you choose the right character and guide for your situation then you should get to 70 in a matter of a few days /played.
First off lets look at each class and how difficult that class is to solo with:
Rogue - The best choice for soloing. A rogue is not meant to be a tank but it can certainly kill fast which increases your experience per hour!
Warrior - Not the best soloist but can tank up to 4-5 mobs depending on gear.
Mage - I like soloing with a mage because even though they wear cloth armor they usually never get hit with all the stun and freeze AOE (area of effect) spells. If you like killing around 10-15 mobs at a time I would find a decent AOE mage build.
Shaman - These guys can pack a punch as well and they can also wear a shield which makes them a little more defensive. This class is not the easiest to solo with though.
Hunter - The safest solo leveling class in the game! Hunters use a pet to tank for them and usually your pet can tank 2 or even 3 mobs at a time while you burst them in just a few seconds. Hunters are not the best at PVP but they are extremely fun to play.