First, and number 1 rule: Do not kill the wyrmtamer mages (the mages that guard aggy). the normal dragoncult mages (initiate, scorcerer, etc) are fair game. Why don't we kill them? each one can heal all the bad guys in the area by 5000 health! Our basic strategy is to drain their energy, and it works very well.
So, here is the breakdown of an Aggy battle.
1. don't worry too much about which group you are in - every level appropriate player will get a shot at the drops
2. There is a primary tank for Aggy, he or she is supported by at least three druids generally. Once the battle gets going, he and his team are generally near the back of the cave, less adds there.
3. there is a tank for the wyrmtamer mages (aggy guards) - we call him or her the punching bag. Their job is to taunt the wyrmtamers and keep them hitting. The wyrmtamers will run out of energy and become non-issues for the rest of the battle. The punching bag has to turn auto attack off (so they don't kill by accident).
4. the punching bag is generally supported by 2 or 3 druids. Some of the main tank druids may support him in the very beginning, until aggy is engaged.
5. there is generally a warrior or two who are in charge of tanking adds (wyverns and mages). There are a lot of adds and this is very important role.
6. Most everyone else (mages, rangers, warriors, rogues) should dispatch adds when they pop up and hit aggy when they are not needed for adds
7. Spell casters should decide their roles and who casts what. For example, only the mage with the highest fire lure should be casting it on aggy. decide which rogue will keep smoke bomb on aggy. who will put bark and wards on tank, etc.
8. Try not to chat too much in beginning, there are a lot people around trying to organize.
9. Stay focused on your roll. This is a team effort and works best, fastest, and cheapest if everyone stays on task.
How we start:
1. once the groups are set and everyone is ready, the punching bag takes his position, and the druids get ready.
2. a ranger fires one shot at a wyrmtamer, and leads him over to the punching bag. A druid should be ready to heal/buff the ranger, cause the wyrmtamers will generally get in at least one shot which will nearly kill rangers. If the ranger dies before the PB taunts the wyrmtamer, he resets and we have to start again. So please keep the ranger alive

3. the punching bag (PB) will taunt the wyrmtamer.
4. Once the first wyrmtamer is under control, the ranger will get the second and repeat. Then the 3rd then the 4th.
5. Now that the wyrmtamers are under control and the druids know they can keep the PB alive. the main aggy tank will engage aggy. sometimes we wait for the wyrmtamers to drain all their energy.
6. kill aggy (i recommend you stand to the side or rear) - and again - do not attack the wyrmtamers - we want them alive!
The beginning is the most difficult time. There will be a lot of adds and a lot of chaos. It can be hard to tell the wyrmtamers from other mages and can be hard for the PB to taunt the wyrmtamers as the ranger brings them in. This is the most expensive part of the battle and many fail and abort at this stage.
Level requirements and joining the battle:
1. warriors, mages, rogues, and rangers must be level 140+
2. druids must be level 120+
3. you must join before aggy is half down if you wish to dice for drops
4. You should be prepared to battle (have idols, do not lie dead, etc.). I would not expect this to be an issue at 140+
Dicing:
There are two primary dicing methods (that have been discussed in other threads - no need to discuss the merits here). I will review them below.
1. at somepoint, generally at the beginning of battle, we will choose a dicemaster. after aggy dies, everyone give dicemaster the aggy drops
2. after aggy dies, we all meet at the second laystone in OW (near the merchant). This location should be confirmed during or before the battle.
3. everyone stands in a circle around dicemaster. Please do not move or talk to much. it is very distracting with that many people. We really dont need dicing to last forever or be annoying.
4. dicemaster will remind everyone of the rules and describe the drops
5. dicemaster will tell when to start rolling and when to stop rolling
6. do NOT screw around with the rolling. only roll once. if you mess around or make things difficult, you may not be invited back.
7. high roll gets the drop
The Dicing Methods:
Class-Based dicing
in this dicing method, we try to assure that drops go to people in the actual battle that can use the drops. A couple of things: for each class restricted drop, each toon of that class may roll (so if you have two rogues, you can roll 2x for rogue drop). for all-class drops, each player gets one roll. Also, each player may only get one drop regardless of alts.
1. we dice the class restricted drops first.
2. everyone of the class will dice when the dicemaster says. If you are of the class, you may choose to pass (this happens because you don't want to chance winning and give up your chance for a different drop later). If there is only one player of that particular class, it goes to them (unless they pass). If there are no players of that class (or all pass) - everyone may dice on it.
3. After class drops, we dice the non-class drops.
4. special rule: as a server we pretty much voted that Tridents are only diced by melee classes (warrior, rogue, ranger) and books are only diced by spellcasters that benefit from them.
note: if you have alts in the battle, your advantage is that you may be able to dice for different class restricted drops. however, only one roll per drop and only one drop per player per battle.
Random Dicing:
In this dicing scenario, everyone may dice for every drop. They may also pass. As above, the dicemaster will describe the drop and tell people when to roll. In this dicing method, you may roll for each alt you had in battle. Players may only get one drop regardless of number of alts.
As a practical note - most dicing will be done class-based. There were many discussions and votes and it seems to be generally (though not unanimously) accepted. It happens to be the requirement of berserkers, so if they are in the group, you can expect it. Regardless, it should be made clear in the beginning so there are no misunderstandings.
i hope i covered all the salient points. if i missed something, i will try to modify this initial post so it can be a reference for newly minted aggy battlers! Grats again on your achievement and welcome to the end game!
thanks