In World of Warcraft quests are easy to find and acquire. Most commonly, talk to an NPC with an exclamation point (!) above his or her head. The exclamation point indicates that that particular NPC has a quest available. A question mark (?) above an NPCs head makes it easy for players to see which NPC they must return to in order to complete their quests. There are also indicators to let players know which NPCs will have quests available in the near future. There are also a number of other ways to activate quests exist in the game.
Quests that have been accepted appear in the players quest log, color coded by difficulty level. The details of each accepted quest -- including the quests requirements, which NPC to speak with once those requirements are satisfied, and the reward(s) that will be available are easily accessible in the log. Quests can be abandoned at any time, and they can easily be reacquired as well.
To abandon a quest, simply bring up the Quest Log (L), find the appropriate quest, and hit the "abandon quest" button at the bottom left. The quest will now disappear and the initial quest giver NPC will again have a yellow exclamation point above their head, ready for you to talk to if you wish. In other words, you can still re-acquire abandoned quests.
Completing the Quest
Your quest log will usually include the character that you are to return to along with the quest description. When you find the appropriate NPC and have all the required quest items (if any), you will always receive xp but may have the chance to choose between a number of items. If this is the case, highlight the item and click the "complete quest" button at the bottom. In other cases, the reward may be set and you'll simply have to click the "complete quest" button at the bottom of the dialogue window.
Overall World of Warcraft Quests Guides
If you’re just looking for directions on how to complete a specific quest, go to thottbot.com, wow.allakhazam.comor wowhead.comand do a search for the name of the quest. You’ll find helpful comments from people who have already done the quest and shared their strategies.
If, on the other hand, you want more of a walkthrough which shows you which World of Warcraft Quests to do in what order, and to Dominate the Game speedily, then you should get tips from the Experts of the Game.