Here is an overview of what talents to use as you level your Warlock along with some level 70 talent builds. The best guide to playing a Warlock I've found is at Killer Guides. You can always make your Warlock better by getting a lot of gold and buying the best gear, to do that I strongly recommend using Valkor's Gold Guide for farming massive amounts of gold.
- Leveling a Warlock
- Level 70 Talent Builds
Warlocks are known for their ability to fear and cause a significant of damage over time on their opponents while they are running away in fear. They are capable of dealing single target direct damage blasts almost as good as a Mage. The Warlock is a very beneficial group member because it has the ability to cast Soul Stone which allows the targeted group member to come back to life for a period of time after they are killed; it's very helpful for group recoveries after a wipe. The Warlock has several pets for different encounters, whether its tanking, incapacitating an enemy, or causing mass amounts of damage, the Warlock has a pet for the occasion.
If you really want to blaze through the levels check out either Brian Kopp's 1-70 Guide (Alliance) or Joana's 1-70 Guide (Horde)
Until the Warlock gets a minion that can tank it can be somewhat difficult to level this class in the beginning. The best thing to do is to cast DoTs on the enemies and fear them. Try to keep all but one enemy in the encounter feared or all if possible. Only one fear can be on one enemy at a time so ensure that before casting fear on another enemy that the currently feared enemy is far enough away so that when its fear breaks it can be recasted on it before it reaches the Warlock. When a tanking pet is available all the Warlock has to do to level efficiently is keep the pet alive and keep enemies away from itself.
The Affliction tree should be renamed to the “Cast some spells and watch your enemy die slowly tree”. The Warlock can torture its victims while they flee in terror only for the fear spell to break and they die on the spot. By stacking a few Warlock damage over time spells on a target most of the Warlock's opponents' life will bleed away.
Demonology can make leveling very fast and efficient. It's not that exciting; send pet in, cast dots, nuke, and repeat. Once the Felguard is an option through the Demonology tree, the Warlock will be capable of dominating both PvE and PvP.
This build focuses on getting another high damage over time spell from the Affliction line. It can be used for PvE and PvP but
it is most effective when all of these spells can be unleashed on the enemy without having the Warlock's
weak pet tank. Shadowburn is added to this build for extra damage.
This is a pure fire PvP build that focuses mainly on direct damage to kill foes quickly. It is a very mana intense build so be wary when attempting to take on multiple targets in a row.