Get a Night Elf Hunter or a Warlock for Soloing
In World of Warcraft, the best character template is on the Alliance side. Warlocks are bit more fragile, and they have an excellent complement of damage dealing spells that will let them survive - albeit while taking more damage. But many creatures will attack in groups if they notice on of their buddies getting pounded on.
The Warlock's Viod Walker is particularly good at pulling one creature away from a group and a time and killing it, that's what we called "crowd control". Night Elves quest lines at low levels are also pretty self-contained within the geographically isolated Teldrassil, meaning you never have far to run to reach a quest destination or to retrieve your corpse. As a Warlock you have to spend some WOW gold to buy a pet.
Gomes have the best dancing emotes
Also we can say Gomes have the worst dancing emotes. Gnomes dancing is the most offensive thing in Azeroth, even there is a rumor says the horde offers 10 WOW gold pieces to anyone who can actually manage to kill a Gnome in PvP during a dance. Therefore it makes Gnomes perfect for role-players who want to annoy other players and have a good laugh.
Human Priest is Popular
Every WOW Player wants to group this perfect class. Humans' racial talents help a Priest hold his or her own in combat and there isn't a group alive that isn't thrilled when a Priest shows up just before heading into an Elite dungeon or an instance. Priests are also pretty rare in the game, there aren't really all that many players who enjoy taking on the social/support roles, so your skills will always be in demand - and you'll do WOW Power leveling pretty fast.
Don't follow the quest lines for your own race
Especially WOW new players have misconception that quests are restricted by race. And it's not true. Players can take any level-appropriate quest regardless of their race. If you are alliance and want to do WOW Leveling faster you can simple head to the hub cities of Ironforge or Stormwind as soon as you are strong enough to get out of the newbie zone which is around level 5. And then find the passage to Teldrassil, the Night Elf homeland and start collecting quests. Teldrassil is very small, contains the hub city of arnassus that offers every service, and players rarely have to run far to complete quests. You'll find yourself at level 10 or even higher in no time!
The Alliance means more content
The Alliance in World of Warcraft races as a whole including Humans, Night Elves, Dwarves and Gnomes are more popular with players. This means the situation that several quests in the area that require players to kill a particular animal may make it hard to find that animal for a while because you maybe racing other players who are standing around waiting for them to spawn. So the Alliance has a lot more quest-based content than the Horde. While this isn't noticeable at the earlier levels, many Horde players often find themselves running low on quests around level 25-30 and being forced to just "farm" random creatures for experience.