Wow Wiki is a great site if you want to learn more about the game. It is basically an encyclopedia of all things in World of Warcraft.
Wowhead is a great source for getting specific information or data about the game. It is a giant database of all the items, quests, NPCs, and more in World of Warcraft. There’s a thriving community of fellow WoW players who frequently leave comments on each entry so if you’re ever stuck Wowhead is the best source to figure things out.
Noxxic is easily the best resource for World of Warcraft PvE and PvP class build guides to maximize your classes’ efficiency.
Official World of Warcraft Website
This one may seem obvious but the official World of Warcraft website is the best place for the latest news and info about changes occuring to the game, especially new patches or expansions. Being one step ahead of these changes can prepare you for what’s to come and really speed up your performance as you don’t have to learn everything as you go.
If you really want to get the steam engines burning and start leveling your characters in record speed then you really need to get your hands on a professional leveling guide. These are in-game strategy guides which run inside the game like an addon and will really give you a huge advantage. The absolute best guide on the market for the past 5 years is Zygor’s Leveling Guide. They give you an optimized questing path used by the pros to power level your characters in literally just 5 days played time. The best part is that it is completely safe and legal to use and it also has a free trial from level 1-20, and the only drawback is that you do have to pay for the full version. But honestly, you will get so much more done with your time that it literally pays itself off in no time.
More detailed review of Zygor Guides can be found at homepage http://zygor-vs-dugi.com/
Dugi team has spent over 7 years developing the Perfect solution for players to enjoy extremely fast leveling system which is easily used by players with little or no experience of playing the game. Dugi Guides will always be at sync at optimal leveling rate even if you use heirloom items, use a Recruit-a-Friend, gain experience from PVP or from Dungeons. Dugi Guides also has a free trial from level 1-20 so you can find out yourself how fast and easy using Dugi Guides is!
More detailed review of Dugi Guides can be found at homepage http://zygor-vs-dugi.com/