World of Warcraft starts off as initially a level grinding game. Depending on when you join in, the road from level one to level cap can be a long, at times tedious experience. The journey from being a starting area character to a capped out character is what can either keep a person interested in World of Warcraft or quitting.

It all depends on how one levels. Some level casually with friends and are more into the social aspect of the game. But many simply go at it alone and get discouraged at the amount of leveling required. But leveling alone can be less painful, as long as you go into it with a plan. Grinding can be efficient, and can despite the time invested gain levels and cash in the process. There are three ways to go about this: grinding off mobs, off of quests, and off of constant instance running.

So put on the music, have a few snacks, and put aside a few hours and prepare for the grind.

Guilds are the new power level machines.

With the inclusion of guild 'leveling' in Cataclysm, many have used the experience increases to outright speed a character's experience gain. Add that onto gaining access to heirloom gear from guild specific vendors, guilds themselves are a way to power level.

Instance with a high level.

Asking that high level guildie of yours to run an at level (or above level) for you is also a form of wow power leveling. Unlike in twinking where a under leveled alt sits towards the entrance to avoid gaining experience, a high level will normally run in and gather many mobs while the lower level hangs back not attacking until the high level has all threat.

The low level would be say a room away while the mass farm happens so that they can then leech the experience and have rights to roll on the item drops. This tactic can also be used in killing mobs outside of instances.

Kill mobs in groups efficiently with friends in high places.

Normally in farming mobs along, one goes for green wow power level mobs because of the easier time in killing them. But if you have a high leveled friend, one can by pass this by grouping with and having the high level area of effect higher leveled red mobs, netting a low level lots of experience in a shorter amount of time. Doing this while questing will net the high level things to sell, and you faster quest completion alongside the experience gain.