You are most likely like I used to be - you wanna level a priest so you start Googling and researching on forums about how well priests do in the leveling process, how fast can you get XP and more important: how well can priests manage their mana, because who in their right mind likes to /drink after every mob they killed. The results you might find on the internet may get you down and make you aim for a different class. Why? Because 80%+ of people rank Priests in the lower tier when it comes to leveling in Vanilla. That's just a big pile of bullshit and those who claim that are most likely just rejects of this game, people full of frustration and whatever else you wanna call them.
It's common knowledge that Warlocks and Hunters are ranked as top tier of the leveling hierarchy because they have pets. However, I personally think Priests are the easiest to level up. Why? Here's a quick list:
- You are extremely mana efficient - I finish a fight with at least 90% mana left;
- You are the best healing class in the game, that means you can sustain yourself a lot;
- You have a shield and armour buff with 0 CD - armour is a big thing in Vanilla;
- You can heal dungeons at your level regardless of what spec you chose to level as;
- You can kill gankers if you got a little bit of skill (and if you choose to level Engineering - not mandatory);
How is this possible? There is no big secret, all you have to do is get Spirit Tap 5/5 in Shadow Tree as soon as you hit level 14 and Improved Wands 5/5 in Discipline Tree by level 19. After you get these two talents all you have to do is to make sure you have the best wand you can get at your level (AH is a good place to check that). You can expand into any talent tree you deem fit, however Shadow makes it easier just by a bit.
Follow this easy "rotation":
Mind Blast -> Shadow Word: Pain -> Wand -> Dead
Make sure you maintain Inner Fire and Power Word: Shield on you as much as you can. Doing so will allow you to fight 2-3 mobs at once and finish regular fights with no less than 80% HP and 90% Mana. By the time you engage the next mob, Spirit Tap will replenish your mana to 100%.
I hope this summed it up pretty good for you if you wanna get into the Priest class but got second thoughts because of people saying it's a slow leveling class!