World of Warcraft begins from a high level. You do everything like Leveling or questing is just a way to learn how to play your class. Everyone wants to level up as fast as possible. There are many factors influencing the speed of leveling. It is important to take the right quests, to choose useful talent tree and to choose the specific class and so on.
If you want to level up as fast as possible, you should know what the best talent tree is. Warlock is a pure DPS. You may think that it is not important to choose talent tree, as long as they are all for damage. But that is not correct. Mana efficiency is the big factor influencing leveling. It means that you need a talent tree that you don’t need to drink so often.
You have improved your damage over time as Warlock. You become very good health drainer with talents “Soul Siphon” and “Siphon Life”. When you “Tap” (Warlock’s unique ability to turn health into mana) you can easily recover your lost health. When you leveled your Warlock you didn’t need to stop for drinking at all. Some players prefer to level up as a Demonology. But it was slower and a bit less interesting, because your pet does job. It was not fun for me. The last tree is Destruction which you recommend that you stay away from it while leveling. You will lose your nerves if the mana is inefficient.
Questing is the best and fastest way to get experience points. But you shoud be attention to the fact that Blizzard created large amounts of quests with the intent to slow you down. These quests will reward you with little experience points and take you a lot of time to finish them.
Whats more, if you want to level up faster and simpler, there are many persons doing the power leveling. You could search the wow power leveling on the internet.