Basic Party Strategy

[Artega]

**Warrior**  Usually if there's only one warrior, he'll be the designated tank.  In the lower level instances, having maximum damage mitigation isn't as important (for a war) as being able to hold agro on multiple mobs at the same time.  A warrior as a tank should keep an eye on all mobs in a pull.  This way the warrior can go after mobs that make a mad dash for the casters.  To keep agro on multiple mobs, the warrior will need to use various AoE skills in conjunction with large agro single target skills on the mob everyone is attacking (tactical mastery helps).  Hamstring on runners helps when the group lacks other classes with good snares.

Piercing Howl is generally a better snaring solution than Hamstring; it's instant, area-effect, and causes a modest amount of hate. Later on, Warriors will need to be frequently switching targets to keep hate on themselves in five-man instances. In raid instances (such as Stratholme, UBRS, and possibly Scholomance), you'll generally want to have a Warrior, Mage, and Priest in every group. Each Warrior is assigned a specific target to tank, with the best-protected Warrior (typically Prot spec) taking the strongest mob (boss, particularly dangerous elites, etc.) The group kills the Main Tank's mob, then moves on to the other tanks' mobs. Any non-elites are destroyed by mage or warlock AE.

**Rogue**  The lower level the instance, the more a rogue can be a tank (for one mob at a time).  When the group already has a tank, the rogue helps with agro management by using feint to not get unneeded agro.  Vanish/evasion can also be used in emergencies.  A good rogue can be tough to kill and the healer can focus on other classes first.  Sap will be useful as a form of CC.  The rogue is a good class to be a main assist or a peeler.

Rogues are useful for lockpicking and are excellent as MAs in later instances. Though a bit risky, it's entirely possible for a Rogue to tank a tough mob with Evasion. Case in point: a Rogue can tank the Princess in BRD through use of Evasion while the rest of the group quickly kills the Emperor, thus allowing you to acquire and complete the quest.

**Mage**  The mage is useful for dealing damage and having an excellent source of CC.  A good mage will have a feel for how long his polymorphs last and be able to reapply polymorph before the mob has recovered.  Mages can also get a feel to how much hate their spells generate so that the don't burst too much.  Frost nova will sometimes help as a short-duration CC.  Additionally mages can try to manage their mana (when beneficial) to be in line with the primary healer's mana such that as little downtime is needed.  Some instances will require cure curse.  In most high level instances, instant arcane explosion and improved counterspell will be VERY handy.  Mages are a primary damage dealer and should use an assist macro.

You basically can't do later instances without a mage. While it's doable, it will be MUCH more difficult, and MUCH slower; The Lyceum is entirely possible to do without a mage (we had two Shaman), but it's much more difficult (we wiped once), and a fair bit slower.

**Priest**  Priests will usually be designated as primary healers and sometimes that means not casting any damage spells in the pursuit of group efficiency.  When possible, it's a good idea not to use HW: shield in combat as it appears to draw more hate then heals.  Greater heals can be used on tanks with good armor while flash heals will be necessary on softer classes.  People tend to get nervous when their health drops below 50% and depending on the instance it might be good to keep everyone above when possible.  In certain instances, mind control and shackle can be used to great success.

Completely vital to later instances. Druids are acceptable MHs early on (up until after Maraudon, usually), but the lack of a mana-efficient fast heal (like Flash Heal) and Power Word: Shield make them more limited. Their combat rez and Mark of the Wild are incredibly powerful, however.

**Hunter**  Hunters bring a good amount of sustained DPS to the group while being relatively low-maintainence in the way of healing required.  Their freeze trap can be useful as a form of short duration CC to an incoming mob or as a safety placed on the healer for the beginning of the fight.  They can feign death to remove agro from themselves and use their pets to taunt mobs off casters.  Hunters can also be on the lookout for patrols on the minimap with tracking.  Hunters are a primary damage dealer and should use an assist macro.

Pretty consistent damage, but they aren't a replacement for a Mage by any means. Pets make acceptable offtanks, and Hunter's Mark is invaluable for raid organization. Give Warriors the ability to put big red arrows on mobs, though, and you'll probably see a few less Hunters in raids :)

**Warlock**  The warlock is sort of a magic niche-filler.  The imp group stamina buff is appreciated and it does pretty decent damage for a pet.  The succubus can offer CC through mesmerize.  The voidwalker can be used as CC to keep a mob busy at the beginning of a fight.  The felstalker can eat up magical debuffs or monster buffs.  The warlock himself has banish which is a useful form of CC in some situations.  A good warlock will know which monsters will run away on low health and apply Curse of Recklessness (rank 1) to them.  A warlock also can place soulstone on a rezzer and provide healthstones to the main tank and/or mage (who's using AoE).  Warlocks have decent AoE options and alliance ones can cast uninterruptible (with the help of a paladin and talents).  The warlock should use an assist macro before placing any DoTs on a target.

Warlocks are definitely a niche-filler. They aren't as good as Mages at damage, but they're invaluable to raids nonetheless. Soulstones are wipe-preventers (in most cases), Healthstones are excellent for when the priests go OOM and we get adds, and their summoning assists in quickly assembling the raid group. DoTs can quickly add up, especially on boss mobs.

**Druid**  The druid is an all-around niche-filler.  However, in the higher levels the druid will need the right gear or talents to fill in different roles.  A feral druid with good armor and stamina can tank well in bear form.  A restoration druid with decent int and spi can heal well enough to be a primary healer.  Cat form is underpowered in the higher levels and not as useful to use.  The druid may be called on to act as group healer in the higher level instances because of a general lack of priests.  A good druid will change into bear when he gets a lot of agro at once (possibly cheetah in Zul'Farrak).  Regrowth spam may be required to heal mages that are bursting with Arcane Explosion.  Healing touch can be used on tanks and it might be a good idea to hotkey two different ranks of the spell.  Cure curse and disease will be necessary in some instances along with entrangle and hibernate.

I've yet to see an effective Druid tank at the endgame, but they make excellent backup healers, and their buff is the best in the game. Combat rez adds many possibilities, though Soulstones can do pretty much the same thing.

**Paladin**  The paladin is a good buffer and will need to pay attention to when blessings drop.  Playing a paladin well requires pre-battle thought to which blessings and seals would be most beneficial to use against the coming fights.  They can offer some in the way of emergency or touch-up healing.  A paladin can be the safety for the group by casting blessing of protection to save a caster from death or divine intervention to same the group from a corpse run.  Cleanse will be very useful in many instances.  The paladin should use an assist macro for when he melees.

I don't play with Paladins, I kill them. But I'd assume they're something like a harder-to-kill version of Shaman with lower DPS.

**Shaman** not enough first-hand observations/experience with high level instances.

Shaman are kinda like what I'm assuming Paladins are like - support classes. Their totems (particularly Windfury) come in handy, and they have healing that's good enough to keep an offtank alive. Their Reincarnation ability is a last-resort wipe-preventer, but the amount of Shaman that forget to stock up on ankhs is alarming.

EDIT: Fixed quote tags.
EDIT2: Improper word usage. Need sleep.