There are three general rules you must follow when leading a raid, if you take anything away from this guide, take these rules with you.
Plan all aspects of your raid well ahead of time
Make clear decisions and goals and stick to them for the duration of your raid
Delegate portions of the raid to trustworthy advisors
Make sure the goal of the raid is planned out in advance.
State it clearly and plainly on your advertisement and state it again before the raid starts. Do not deviate from your plan no matter how many people ask you to. If you have a goal and it is achievable, go for that goal only. If you DO change direction, do it quickly and firmly. It is generally a bad idea to ask the whole group where they would like to go as it creates separation within the single body. Talk to trusted advisors if you need to make a change and when the change is made, follow through with it. Firmness is very important on these raids. Don't be nasty, but people will be far more likely to run into battle if they know there is a plan and a goal.
Practice leading raids on lower level dungeons or overland areas where disaster isn't too difficult to recover from. Once you have a good feel for how to lead a raid, take it to bigger dungeons. Unrest is a great place to start. Everyone above 20 knows that dungeon really well and any level 50 player can roam almost freely to drag corpses or defeat troublesome mobs. There are many mid level dungeons that can be used where adventure is high but risk of disaster is low. Use these places to get a feel for leading a raid before stepping up to the larger dungeons.
Preparation (One week before the raid)
At least a week before any raid can begin, a leader must do the following:
Find a location and learn as much as possible about it including maps, loot lists, and hands on experience.
Plan a goal for the raid. Advertise the raid on various guild bulletin boards and in game. Include the raid's specific purpose, loot rules, and who can attend.
The first step in leading a successful raid is proper planning. This means scheduling and advertising the raid well in advance of the time you will run it. It is difficult to get that perfect number of players who attend, you will either get too few or too many so plan ahead on how you go about advertising. If you invite multiple guilds to attend, expect a good number of players, but if you make the level restriction high, expect fewer. If you do a sign up, you can have a better idea for how many and what classes you expect, but risk not having people show and having to scramble at the last minute. The majority of raids I run are open invitation, not sign up, so whoever shows up can join. This makes group building more difficult as new players will be showing up while you are building groups and will come in and drop out during the actual raid.
A wise adventurer once told me that he hunted Sebilis during the to get enough experience and money that when he died on raids he didn't care. He had accepted the most likely outcome of a traditional raid. Raids are not meant to get your character up to level 60 or to give you the latest 20,000 plat item. They are meant to defeat creatures that cannot be defeated by normal groups. If you want experience and loot, go to Sebilis. Raids exist to have fun. This should be made clear to all who plan to attend your raid. With up to 40 people, the odds of willing good loot and good experience are slim. Standard can-and-will-use loot rules are always a good idea to establish when you announce your raid and before the raid begins.
Part of the planning is making sure you know the area you are raiding very well. If you are leading a raid into Kaesora, make sure you know that dungeon like the back of your hand. Spend a lot of time adventuring there, read the maps and keep them with you. Bring along experts who can lead your groups through the twisting corridors and help you avoid traps. The more you know the dungeon, the better your raid will be. While it is possible to raid a dungeon you haven't been to before, it is far more likely to end in disaster if you don't know exactly what you are doing or where you are going. Maps can only take you so far, you really must have good personal experience in the dungeon and understand the pulls and the tricks. Web sites like Allakhazam's and EQ Maps can give you a lot of good background material for raids.
Delegation (Two hours before the raid)
There are so many pieces that need to come together in order for a good raid to work that no single person can handle them all. It is always a good idea to break up the raid into individual tasks and assign them to volunteers so that you don't have to worry about them. These roles include:
Loot Master: This person will make sure that all items are announced with stats and who will roll on it. They will handle all questions or problems as it relates to loot. Since loot is generally important in peoples minds, assign it to someone you know is capable of handling the issue. A loot master should have a good understanding, and ideally a list of what drops can occur.
Transportation Officer: This works best if they are a druid or wizard. They coordinate the arrival of all those who wish to attend. The transportation officer is not solely responsible for moving people to the raid site, just making sure that they are on the way.
Puller / Scout: A monk and / or a rogue work well as scouts. They can pave a way through a dungeon, finding out what the various pulls will include. A fighter, paladin, shadowknight and ranger can also make good pullers. Experience in pulling is a must for this work, so pick someone you know can handle the job.
Primary and Secondary Assist: Generally your biggest and toughest melee will act as the primary assist. Make sure to announce to all in attendance that they are to set up a hotbox to assist the primary assist. Should the primary die, have a secondary assist planned out.
Advisors: Advisors are players that are experienced with the dungeon and with raiding. They will help give you information or make decisions but will not attempt to take control of the raid. Pick people you trust and have worked with before. Assign people you know and trust in these roles and make sure it is clear to them what they need to do. This can cut a lot of the tells you will receive and allow you to coordinate the rest of the raid.
Groups As you get closer to the actual raid, perform the following tasks about an hour before you scheduled the raid:
Assign a loot master, transportation officer, puller and scout, and a primary assist.
Take a sheet of paper and list all the players with names, class and level.
Build your command group including the puller, scout, and any advisors.
Build all groups out of the list, include a healer for each group and mix up the classes so no one group is much more powerful than the others.
The first group you must assemble when building a large raiding party is your command group.
Your command group consists of the following roles; the raid leader, a scout, a puller and primary assist, raid advisors, and any accessory classes such as evacers, healers or mezzers.
This group will act as the command team for the rest of the raid. It determines where the raid heads, and what mobs the raid pulls.
This is the group that makes all the decisions as to where to go and what to kill.
Healers (mandatory) (Cleric, Druid, Shaman)
Evacers (Druid, Wizard)
Tanks (Warrior, Paladin, Shadowknight)
Damage Dealers (Rogue, Wizard, Monk, Ranger, Warrior, Paladin, Shadowknight)
Buffers / Debuffers (Shaman, Bard, Enchanter, Druid)
Other classes can fill out any group, but the two primary roles that must be filled are Healer and Evacer if you plan on evacing.
While you shouldn't worry that a perfect distribution of kills is occurring across all your groups
try not to make one group alot more powerful than the others.
The group leader is your primary point of contact with that group and you should seek feedback about that group from the leader. Have them assign a primary looter for that group and stick with it.
Periodically through the raid, ask the group leader if his group is seeeing too little or too much experience, or find out about any other problems. Manachecks are also a good idea throughout the raid.
The leader of the group should be someone you have worked with before, trust, and understand. Communication is a big key to a successful raid.
Beginning the Raid
As a raid begins, the leader should announce the following to those attending:
The goal of the raid
Loot rules and name your lootmaster
Groups using the "group number: LEADER member member member member member" format
The primary and secondary assists, remind the group to use /assist target.
As a raid moves in, make sure to keep to the following guidelines
Start the raid on time. Only if you don't have enough to move should you stop.
Do not stray from your initial goal.
Make sure to stick to your original plans and loot rules.
Roll on items quickly, upon the drop.
Announce any group changes as you go, but do not change the groups unless you have to.
Do not stop to invis more than one group. Any more than one group is too likely to have an invis failure on the way and force a battle you weren't ready for.
The Corpse Recovery
Plan on the worst disaster you can imagine
Have monks, rogues and necros ready to drag corpses
Know where safe areas are to res.
Inform the group leaders on the status of a corpse recovery
The best raids can sometimes end up in a wipeout where every member is killed deep in the middle of a horrible dungeon. Make sure to plan ahead for such disasters. If you expect groups to evac their members out should a disaster strike, make sure it is clear to every group and to the evacer for that group. You are in charge of yelling evac, but group leaders need to tell you if their group is in serious trouble. Sometimes death is a better alternative to escape. Raids are sometimes brought back online easier if they are simply ressed where they lie. Make sure this is clear if this is the case. If death does occur, have a plan for dragging corpses to a safe area for resurrections, or have a lot of coffins handy. Monks and rogues make for great corpse recovery. Know the safe spots of the dungeon so you know where to drag to. Make sure the risk is known to the members of your raid before disaster strikes so they know exactly what they are getting into.
Ending the Raid
Follow these guidelines for ending a raid.
Have an ending time in mind as you plan your raid.
Don't get greedy, end gracefully.
Assign transport to each group
Have all groups teleport out quickly, they can decide where they can go once you have left.
Distribute any loot that was held to the end after you have left the area.
Probably one of the little known problems that frustrates me the most is getting everyone out of the raiding area quickly. Invariably groups stand around and discuss where they are going and who wants to end up where. Meanwhile big mobs start respawning and killing those who didn't leave on time. As the raid leader direct everyone to port to South Ro, and have them worry about where everyone wants to go from there. As a raid leader, you should be in the last group to leave so if there is any crisis you can take care of it personally.