Horde power leveling

Things go slow in the start of the start. So whatever race is your choice, complete your starting area. Then grab the walking stick.

Levels 5 - 10: Durotar, Mulgore, Tirisfal Glades, Eversong Woods
Durotar is considered by many to be the worst starting areas. However, many people do not. When you start off, you'll need to pick up as many quests as possible. I recommend not looting the mobs because it just adds a few more seconds to the leveling process. Not looting the early mobs of starting zones can significantly reduce the time to complete the zone.

Mulgore is the starting zone for the Tauren. With Cataclysm, it was revamped. However, this does not make it more complicated, rather, it makes it easier. This zone is by far in my opinion the longest starting zone to complete. Again, that is just my opinion. Just pick up and quests you find and do them.