Area of Effect parties are challenging, risky, and rewarding xp parties. The general idea is for a puller, usually a fast heavy armor class (Lineage 2 gold), to gather several mobs at once, and then kill them all at once. There are two main ways of doing it: Pole arm tanking, and Hate tanking. There is three phases in AoE tanking. The first is the Setup, the second is the Pull, and the third is the Kill.
The setup is the easiest part, but often overlooked. First, determine how you wish to pull: Hate or Pole pulling. Dwarves, Destroyers, and Warlords are your best bet here for pole pulling, due to the C4 polearm rebalance. If you have a pure tank pulling, you will want to do hate pulling. The party should consist of at least one healer, and classes (Lineage 2 money) with aoe skills: essentially nukers and polearm users. Overlords are useful as well.
A good location is also extremely important. Using a corner or other terrain feature to herd the mobs into an appropriate blocking angle helps dramatically. The main tank is often also the puller, but this is not always the case. Sometimes a party will have a fast DD such as an archer, dagger, tyrant, or heavy armor classes pull for the tank. This has some distinct advantages: the tank is at full health when the mob train arrives and more mobs can be pulled in less time.