EXP Parties: The Basics

1. Location
   
   Sometimes referred to as "base", "base camp", or "camp".The location is where you and your party will set up shop. The ideal location has mobs that:
• Are 3-5 levels higher than the party
• Continuously spawn
• Do not use abilities like Sleep, Sleepga, Bind, or otherwise not dispellable by the healer or other supporting class.
• 
  
• Will not aggro the party when spawned
• The location itself should be within a reasonable distance from a aetheryte or other means of transportation and a repair vendor.
• It is safe to say, not every location will have these criteria, but it is helpful to understand what makes a location great for your and your party.
2. Party Roles:
• Tank
• Healer
• Damage Dealer (DD)
• Puller
3. Party Role Responsibilities:
• Puller - The puller is typically a ranged class. The puller is responsible for keeping mobs coming in at a pace consistent with, or just ahead of, the rate of killing. This ensures that each kill stays in under the exp chain timer. The puller is also responsible for knowing which mobs to pull, and how far away he can pull from before the mob resets. The puller must know how to avoid mobs that will aggro (by knowing that mob's aggro radius) and how to avoid damage on the return to camp.
• Tank - The tank gets to tank as usual with one exception: the tank does not initiate the fight. The fight initiation is left to the puller and upon the puller's return, taunts the mob off. In some cases, the party might have another mob "on deck" or next to the party, CC'd (e.g. sleep). The tank would be the first to initiate the attack on this mob in this case after the initial mob is dead or near death.
• Damage Dealer - Simply put, the damage dealer's biggest responsibility is to not be a dick and not take damage. The DD should maintain a high level of damage output while taking care not to steal hate (aggro/threat) from the mob. The DD should be mindful of their position to the mob and the mob's special abilities. If the DD is taking damage it should be for the rare emergency taunt off the tank to prevent tank death; all other instances should be avoided. The DD might also be asked to CC a mob to be placed on deck.
• Healer - The healer has a shifting priority depending on an active pull or not. If the puller is about to pull, the priority is: Puller> Healer > Tank > DD. If the pull is done, the priority shifts to: Tank> Healer > Puller > DD. Dispels are always secondary to heals unless on the puller on an active pull. The healer should also be mindful of pulling hate from either the puller or the tank. The healer might also be asked to CC a mob to be placed on deck. The healer should also be dead sexy.

Please see guide on being an awesome party member: http://www.reddit.com/r/ffxiv/comments/1kpl3m/guide_performing_effectively_in_a_party/