Raids are a multitude of groups linked together, and require good leadership and coordination to work well. For any raid you are going to have general rules for everyone to follow (Don’t run ahead of the raid, never get aggro, don’t pull anything unless you are the designated puller, etc).
Currently, these are the 'relevant' raid instances in game: Karazhan (10), Gruul's Lair (25), Magtheridon's Lair (25), Serpentshrine Cavern (25), The Eye (25), The Black Temple (25) and Hyjal Summit(25)
In the pre-BC days, the raiding instances were:
The Molten Core(40), Onyxia’s lair(40), Blackwing Lair(40), Zul’Gurub(20), the two Ahn Qiray instances(20 and 40) and Naxxramas(40).
Few guilds go to the old level 60 raiding instances, as the rewards just aren't worth it anymore compared to what you can get in Outland.
Lastly, Blackrock Spire is a 10 man instance in the level 60 range where people can get their first taste of raiding.
In addition to raid instances, there are outdoor raid bosses which can be engaged with a raid of 40. Outland contains two; Doom Lord Kazzak in a secluded are of Hellfire Peninsula and Doomwalker outside the Black Temple.
Azeroth has six level 60 outdoor raid targets; Azuregos, a dragon in Azshara and Lord Kazzak the demon in the Tainted Scar, in the southwest of the Blasted Lands. The remaining four are dragons spawning at portals around the world; Lethon, Emeriss, Ysondre and Taerar. They are found in Ashenvale, Feralas, Duskwood and The Hinterlands.
The Outland bosses especially are contested targets, and guilds may be racing for them when they spawn in order to get the kill before another guild does. As with instances, the Azerothian raid bosses aren't nearly as popular as they used to be.

All classes have one or more specific tasks on a given raid. Warlocks will get asked to make sure that certain curses are kept on a raid target at all times. Bosses in Karazhan or Gruul and beyond are tough fights for newer guilds and they can take a while to kill. Curses can make a big difference here. You are also tasked with putting up a Soulwell every now and then as well as keeping a soulstone effect on someone. If its your first

time visiting a new raid zone as a guild, make sure to bring plenty of soul shards. Chances are you are going to die a lot and not have alot of opportunities to drain new shards. You may wish to cut back on pet summons and use an imp as well as limiting your usage of shadowburn and soul shatter to the times you really need them to preserve shards. In some cases you may be placed on add control and get assigned a demon or elemental to banish, or a humanoid to seduce. Imp is a good choice for raiding due to his stamina buff. In some cases, another pet is a better idea. Your talent spec and which group you are in (tank group?) factors in on pet choice as well.
Beside that, you should do your best to sustain the highest possible damage output without stealing aggro. This is easier said then done. Suffice to say, you will be in combat mode the entire fight, so drinking is out of the question. Mixing DoTs with nukes, you should be able to sustain a good damage output for a long period. How easy that is when healing is limited depends on your spec.
A thing of note: Be careful with Eye of Killrog on raids. While this shouldn’t be happening, some bosses will trasfer aggro onto you (and as such, the raid) after killing your eye.
Arcatraz Key Quest Walkthrough
This quest is not a requirement for entering Arcatraz. In fact, only one person in the group needs a key and it is possible to pick the lock as well. However, should you want a key, here is the questline to get it. Most of this questline can be done solo. You begin with speaking to Nether-Stalker Khay'li in Area 52.
1.Consortium Crystal Collection
A straightforward quest, and a very easy one at that. Note that you can retreive the Crystal from both Pentatharon and Ekkorash the Inquisitor, the latter of which being summoned during the 'The Archmage's Staff' quest. The follow-ups take place in the same general area.
2.A Heap of Ethereals
3.Warp-Raider Nesaad
Nesaad is found west of the other ethereals near the Fel Reaver southeast of Manaforge B'naar.
4.Request for Assistance
Travel to Eco-Dome Midrealm for the continuation of the quest.
5.Rightful Repossession
Collect Boxes of Surveyring Equipment by Manaforge Duro.

6.An Audience with the Prince
Speak with Nexus-Prince Haramad at the Stormspire.
7.Triangulation Point One
Point one is located a ways east of the Protectorate Watchpost (loc: 66.7, 33.8). Use the Triangulation Device to find it, then get the follow-up from Dealer Hazzin (at the Protectorate Watchpost);
8.Triangulation Point Two
The second point is found a little east of the entrance to Manaforge Ara (loc 28.9, 41.2). turn this quest in by Tuluman's Landing, a small outpost by the bridge leading to the Manaforge Ara island.
9.Full Triangle
This quest is meant for two, but can be solo'd using a Voidwalker or Felguard to tank the elite. You can find Culuthas in the northeastern tip of the island Stormspire is located on.
10.Special Delivery to Shattrath City
You can use the portal in the left of the Nexus Princes' room to teleport to Shattrath. Upon turning this in, you receive a 2 hour buff granting you 200 melee and ranged attack power as well as 115 spell damage.
11.How to Break Into the Arcatraz
A'dal asks you to retreive the Top and Bottom Shards of the Acatraz key. The Top Shard is found from the last boss in The Botanica, Warp Splinter. The Bottom Shard is held by the last boss of the Mechanaar, Pathaleon the Calculator.
Once you have collected both, you can turn them into receive your Arcatraz key. You will receive one last follow-up to kill a boss in The Arcatraz.
Karazhan Key Quest Walkthrough
You can begin this questline at level 68, but you will not be able to progress beyond a certain point until you are 70. The questline is the same for both factions.
Start by traveling to Karazhan in the south of Deadwind Pass. By the entrance you will find Archmage Alturus, who has two quests for you;
1.Arcane Disturbances
2.Restless Activity
Both are doable solo. Note that the Well and Pond are each in a different underground area, the entrances of which are the cellars of two ruined buildings near Alturus.

Once you complete the two quests, you receive the next one;
3.Contact from Dalaran
You will find Archmage Cedric north of Dalaran along the shore. He gives you;
4.Khadgar
Speak with Khadgar on the Terrace of Light in Shattrath. He sends you to the Shadow Labyrinth. This is still doable at 68, but I would recommend level 70 for this step and the ones beyond it;
5.Entry Into Karazhan
You need an Arcane Container, which can be found along the wall in the final room of the instance. There happens to be a boss in that room, but its conceivable that you are skip that boss and grab the container. Note that an elite elemental spawns from the container, which must be killed in order to get the key fragment.
6.The Second and Third Key Fragments
After returning to Khadgar, you receive the above follow-up which sends you to two instances. The container in Steamvault is found in water not too far from the entrance, close to the ramp leading up to the first boss on the left. The container in Arcatraz (requires a key or lockpicker, level 70 and flying mount) is harder to reach, it requires you to clear a ways into the instance until you reach the first room with voidwalkers in it. The container is in this room, to the right. It is possible to avoid killing the voidwalkers, provided you wait for them to both path far enough way from the container. There will be a moment to open the container and pull the guard that spawns back out of the room to kill safely.
7.The Master's touch
You now have the key, and are tasked with going to the Black Morass to get Medivh to activate it. This requires finishing the instance successfully, after which you can speak with Medivh to finish your key. When this is done, return to Khadgar to receive your Karazhan key!
The questline continues beyond this, rewarding you an epic trinket with arcane resistance in the end.

Onyxia Key Quest Walkthrough
Note: this quest is for a pre-Outland raid, and is not interesting for the average player anymore. I'm leaving it here in case you are interested in getting the key anyway, for completeness sake or whatever other reason.
Entering Onyxia’s Lair requires you to do an involved quest to obtain a key. Everyone in the raid will need a key to get in, and everyone needs to do the quest. This is no cakewalk, and it takes a lot of effort to do.
Alliance
Complete the quest ‘Dragonkin Menace’, given by Helendis Riverhorn in Burning Steppes.
You are then told to deliver a letter to Magistrate Solomon in Lakeshire, who then tells you to speak with Highlord Bolvar in Stormwind. (Palace) He sends you back to Magistrate Solomon, who in turn sends you back to Burning Steppes. Speak with Maxwell, then speak to Ragged John in the North of the zone, east of the mountain entry. Back to Maxwell, and he will tell you to find Marshall Windsor in BRD. You will need a prison cell key. As you enter BRD’s first big room, enter the middle of the most right three tunnels. Its different from the others in that its stone instead of a rough dirt tunnel. At the end of the tunnel is the High Inquisitor, who drops the cell key. One of the cells in the adjacent tunnels has Windsor in it. After speaking to him, you have opened up the chance of a note dropping from random mobs in BRD. When it drops, speak to Windsor again, and he will tell you to kill Argelmach and Angerforge to obtain the rest of his missing notes. Once you do this and return, you are to escort Windsor out of the prison. Clearing the tunnel of enemies before starting this quest can make things easier. Once the escort is over, talk to Maxwell in Burning Steppes. Maxwell tells you to travel to Stormwind and meet Windsor at the city gates. Now for the followup, you are told to need a raid. However currently, Highlord Bolvar can take out everything in this fight by himself. Talk to him after to finish this step. If you fail, go back to the city gates and wait for Windsor to make another appearance.

Bolvar gives you a fragment of the key, and tells you to seek out another helpful dragonflight. The NPC you need is in Winterspring. Go through the caves of Mazthoril southwest of Everlook. You’ll need a group if you intend to clear the enemies, or you can deathrun through it solo. In the last big room of this cave you’ll find a blue rune

on the ground. Step on it to be transported to the NPC you need. Get the followup quest, which is to acquire the blood off of General Drakkisath in Blackrock Spire. You need a raid to kill him, and he only drops one blood per kill. Once you get the blood, return to Haleh in Winterspring and receive the key to Onyxia’s lair in Dustwallow Marsh.
Horde
Speak with Warlord Goretooth on the guard tower in Kargath, Badlands. He gives you the quest Warlord’s Command. You have to take a group into Blackrock Spire, kill three bosses in there, and recover documents. This is quite an undertaking, and tends to take more then one visit to Blackrock Spire, or one very lengthy one. The documents spawn at any of the three bosses, or at Urok’s Tribute Pile. Looting it will make it reappeat at any of the 4 spots at random. Once you complete this quest, you will need to visit Eitrigg in Thralls room in Orgrimmar. Thrall gives you the next quest, ‘For The Horde!’. You are to acquire the head of Warchief Rend Blackhand in Upper Blackrock Spire, which takes 2 -4 groups to do. (4 is quite doable, 2 is very hard).
To get to Upper BRS, someone will need to have a key. (only 1 key is needed to get a whole raid through the door). If no one has a key, you’ll need to obtain one through collecting 33% dropchance gems from the three bosses you’ve killed earlier in BRS. Voone, Omokk, and Wyrmthalak. You need a gem from each, and an Unadorned Seal of Ascension, which is a random drop in BRS. Once you have these items, speak to Vaelan in BRS. He is in a pretty obscure spot near the start of the zone and can be hard to find. Before you reach the first bridge, there is a slope going upward. You’ll need to jump onto a platform there and you’ll spot him then. Turning in the items gives you the key to Upper BRS.

Once Rend is dead (This is a raid quest, so everyone in the raid can loot his head) you get a nice trinket and the followup quest. Thrall will tell you to seek out Rokaro in Shadowprey Village in Desolace.
Rokaro tells you to find Myranda the Hag in Western Plaguelands. It’s a gnome south of Andorhal in the graveyard, standing on a tree stump. Myranda tells you to collect 20 dragon eyes from dragonkin in Upper Blackrock Spire. They don’t drop from the whelps, only the big dragonkin. They drop 1, 2, or none. Once you get 20 eyes, turn them in to Myranda, she gives you an amulet and tells you to travel to Emberstrife’s cave in the sotuh of Dustwallow Marsh. In the cave, use the amulet and speak to Emberstrife. He has a line of 4 quests available, and you will need a full group to do them. First, you are told to kill a dragon called Scryer in Winterspring. Hes in the cave of Mazthoril, full of blue dragonkin and southwest of Everlook. Back to Emberstrife, and you get the order to kill:
·Somnus, east of the sunken temple’s lake in Swamp of Sorrows.
·Next is Chronalis, by the caverns of time area southeast of Gadgetzan.
·Last is Axtroz, in the east of Wetlands.
Once you’ve done all this, Emberstrife gives you the followup. Go see Rokaro, who tells you to kill General Drakkisath, which requires a raid into Upper BRS again. He only drops 1 blood per raid, which is a major pain. Once you acquire the blood, back to Rokaro who gives you the drakefire Amulet, which is also the key to Onyxias lair.
Done!