TUpper Blackrock Spire (UBRS) and Zul'Gurub (ZG) are good places to begin. Upper Blackrock Spire allows 10 players to be in the instance at one point in time, while Zul'Gurub allows for 20 players. From there many guilds head to Molten Core or Onyxia. Both of these encounters allow for 40 players to be in the instance at one time. Ruins of Ahn'Qiraj (AQ20) is a good dungeon for raids that have mastered UBRS, ZG, and Molten Core. Once those dungeons have been mastered, players often challenge themselves with Blackwing Lair (BWL) and Temple of Ahn'Qiraj (AQ40). Last on the progression is Naxxramas, which currently, is the most challenging raid dungeon in the game. Blackwing Lair, Temple of Ahn'Qiraj, and Naxxramas also all allow for 40 players to be in the instance at one time. If you're looking for non-instanced experiences, there are multiple outdoor raid encounters located in many points throughout Azeroth. These can prove to be fun, and challenging. Keep in mind, since the outdoor raid bosses are not instanced, you may end up competing with other players for the victory. You can follow the link below for more information on the outdoor raid encounters.

Before Raiding

Add-Ons
While World of Warcraft comes with many raid interface options, some guilds prefer to use specific 3rd-party add-on programs. Check with your guild to find out if they have any preferences on what add-ons their members should be using. Make sure that anything your guild uses or suggests does not violate the Exploitation Policy before you install it. Also, make sure you're careful when downloading programs from unknown sources, and always make sure that you're running the latest firewall and antivirus software available to prevent the risk of a trojan or some other malicious program from being accidentally installed on your computer.
Voice-Chat Programs
Some guilds also use 3rd-party voice-chat programs to organize and run their raids. They typically create a specific channel for their raid and have members join the channel. The raid leader then gives instructions via microphone and players can listen through their headsets or speakers. Make sure that if you decide to use these types of programs you do not use anything that violates any of our in-game policies.

Learning the Raids
Prior to the start of a raid, make sure that the entire raid party knows which boss encounters are on the agenda. If the raid leaders are familiar with anticipated encounters, make sure that information is shared with everyone in the raid. Most often, guilds will have a section in their forums or website strictly devoted to strategies for every raid dungeon and boss encounter for their members to use as a reference. In many cases some classes have very specific tasks they need to perform in order to ensure the success of the raid group. It's important for everyone to have easy access to this information ahead of time. Understanding the fight is always half the battle!

Raid Materials (Mats)
There are many items that can be useful to have when raiding, such as resistance potions, flasks, healing potions, mana potions, reagents for your class, repair bots, and so on. These items are generally referred to as consumables. Some consumable items are most useful when given to a specific class, while others are items that everyone can take advantage of. In many cases, guilds will stockpile several items for their members to use. In order to have all the consumables needed for the entire raid party each week, materials will often be collected and made available prior to the raid starting. At the highest level of raiding, this becomes very important.

Get It Put Together First!

Make sure that guild members bring their required items to the raid, such as: resistance sets and specialty gear, potions, bandages, reagents, and so on.
Make sure guild members have their required dungeon keys, if needed. Remind everyone prior to leaving for the raid location. Example: "Don't forget your Onyxia key!"
Sometimes, providing lists of items needed for each raid dungeon can help members better prepare ahead of time.
Repair Before Raiding
Make sure guild members repair all of their equipment prior to raiding. This point can't be stressed enough. Having to place a repair bot shortly after a raid begins because a member or several members have broken gear can become expensive.
Having multiple repair bots is still helpful in case the need to repair arises.

Loot
Before raiding, each member should know, understand, and agree on the loot rules. Having this aspect of the raid understood by all will help prevent loot disagreements. If you're unsure as to whether or not to loot, ask.

Master Looter
Many guilds feel that it's a good idea to assign a very trustworthy player the role of master looter. The raid leader can set this option by right-clicking on his or her character portrait and selecting the master looter option. The master looter needs to always have as much available bag space as possible since they will be the primary looter. Having a master looter generally protects the guild from the possibility of someone taking an item without the permission of the guild.

Assist Macro
Players are often asked to make a main assist key in order to target the correct monster in an encounter. An example of a main assist would be a warrior who is engaging a particular monster. Players in the raid will assist that warrior on the target of the warrior's choosing until it has been defeated, and progress from there. By doing this, a raid group can systematically control the pace of the fight as well as control where the most damage is being given.

In order to create a main assist key you will need to create a macro. To do this, type /macro and click "create new." Select an icon and name it "Assist." Then click okay. That icon should have appeared in your macro menu. Click on the icon. In the box appearing on the lower half, type /assist and then the main assist's name. Drag the icon onto your bar. When you press it, you will target whatever the MA is targeting. There are also add-ons that allow raiders to more easily tell whom they should assist.

Creating Chat Channels
Many guilds find that creating multiple custom chat channels can be extremely helpful. Creating a separate channel for each class, for example, allows them to communicate and coordinate class-specific tasks without filling up the /raid channel with information that will not apply to most of the raid. For instance, warriors might discuss tanking targets while paladins decide blessing assignments in their own, class-specific chat channels. This will free up the raid leader to continue to give general directions to the entire raid without interruption in the raid discussion channel. To create a new channel, simply type /join newchannelname.

Additionally, right-clicking on the chat window tab allows you to customize several of your chat settings, including the text color of each chat channel. Many players find it useful to designate different colors for each channel to help them easily spot important messages.

It's Time to Raid!

Starting the Raid
Determine an exact start time for the raid and start inviting people beforehand. Some guilds pass out invites 30 minutes to an hour in advance. This time can be used to make additional checks on supplies and allows people a chance to finish up anything they need to do prior to the raid. It's important to find a positive way to encourage members to show up on time.
Staging Point
Pick a spot for raiders to gather. On a PvP realm it can be dangerous to head out to the dungeon one by one. Instead, it's recommended to gather somewhere, such as at a flight master, before heading out. After the group is ready, head out to the dungeon entrance. On PvE realms, the staging point is less necessary because there is no danger of being attacked by the opposing faction, unless one of your own members decides to flag for PvP.

Summoning
Warlocks can summon players to the desired gathering point. In order to summon a player, the warlock will need a soul shard and the assistance of two other players in their raid party to click on the summoning portal. It's a good idea for guild members to offer their warlocks help from time to time in gathering soul shards.

While warlocks can summon players to the desired gathering point, be mindful that when a raid is scheduled to begin at a certain time, all players should be either at the starting point or in the instance and ready to go. Summoning a few stragglers is often acceptable (or summoning the inevitable person who forgets their key or resistance gear); summoning the entire raid from a major city or town is extremely taxing to the warlocks in your raid. The shards they spend summoning fellow players could be put to better use on healthstones, soulstones, and other spells during the raid. It can also put the summoning group in danger should they be in a PvP area.

Water & Food
One thing mages love to do is to summon food and water for the raid. Okay, maybe they don't love doing it, but it is something that is important for the raid. Give your mages plenty of time to create food and water, as it can take a while depending on how many players are requesting this service. Provide the mages with mana regeneration buffs (paladin/shaman/druid/priest) to help this process go faster.

Organizing Groups
Good raid leaders should have great organizational skills. It's important to look at the raid panel and move all of the classes and groups around until you find the group setup that works best for your raid. Being flexible and adapting as the raid progresses is also important. It's often necessary to make changes to your groups during the raid, as members come and go, new bosses are reached, or if something is simply not working.

Fighting a Boss
Fighting a boss can be one of the most exciting parts of the raid dungeon, but it can also be one of the most frustrating. These encounters are designed to be challenging, so remember to keep things positive, and have fun. Victory will come with some patience and focused play time.

Buffing the Raid
Make sure everyone is buffed prior to the fight. Buffs are the spells that add benefits to another player's statistics. These include such spells as Mark of the Wild, Prayer of Fortitude, paladin blessings, Arcane Intellect, and others. This is a need that every buffing class should be well aware of, and the appropriate materials/reagents (if needed) should always be on hand.

Soulstones (Warlock)
Before fighting a boss, make sure to have your warlocks give soulstones to select party members so that they can resurrect in case of a wipe. Generally speaking, soulstones are used on resurrecting classes. This can help a raid group recover from a bad pull or other miscalculation much quicker and get the raid progressing again. Do not waste a soulstone by using it when the raid is wiping. Make sure it's ok to use one. It's often a good idea for warlocks in the raid to coordinate and stagger their soulstones so that there is always someone with the ability to use one should there be a wipe. Once you grow more familiar with encounters, extra soulstones can be applied to key classes during boss fights, to reduce the need for druids to use their Rebirth ability.