One of the most fundamental skills a Wizard must learn in grouping is how to control how angry a monster becomes at the Wizard. There are basic reasons for this, first of all being if you are hit too much as a character in Everquest, you die. Wizards are especially fragile, being an INT caster, and as such can sustain significantly less damage than most other classes. However, there are other reasons to be careful with aggro that you build up in a group. Even with over 200 chanelling it is difficult to cast while monsters are hitting you, especially if they bash you. In addition, every attempt to cast further aggros the monster at you. Further, when a monster becomes angry at you it will cross the distance and engage you in combat, pulling it away from the melee types. This wastes time for them and if you keep doing it, begins to annoy them.
If you learn to control aggro, you will be able to contribute to your group consistently and comfortably without disrupting the flow of combat and making anyone have to hunt down where the monster ran off to. Not learning to control aggro will make groups uncomfortable and unhappy with you, and in addition it demonstrates you to be a selfish Wizard. When you group, you are part of a team working to a common goal, watching out for each other and working to common benefit. It is a communal effort, you watch each other's back and support each other. Blasting freely without any desire to control what happens and relying on everyone else to support your efforts to kill everything is soloing at the expense of other people.
There are just a few things to remember to control aggression, and in the process control mana burn. First off, the aggro tables are based on some complex concepts, but primarily damage done to the target. If you out damage everyone, the monster will decide you are the most dangerous person there, and begin an attempt to end your life. An additional contribution are non-combat effects that hinder the target. Stunning, rooting, slowing it down, and so forth, anything that would annoy you will annoy the monsters. This is why when you cast Force Shock on a monster, it becomes very upset with you - you just did a lot of damage, and hit it with an interrupt stun effect, a double whammy. This explains why Enchanters have so much trouble with aggro, all their blasts behave like Force Shock, but they have several methods of controlling aggro.
Another issue is resists, which ties into some other concepts such as missed attacks and failed backstabs. If you cast a spell and it is resisted, the monster reacts as if you did full damage to it, and has a slightly higher taunt. In other words, if you had hit with full damage, it doesn't upset them as much as if it resisted the attack totally. Why this is true probably has something to do with the math and forumlas used for taunt that are demonstrably troubled in other areas as well.
A final issue is that of Distance. The further you are from a monster, the more aggro it takes for that monster to turn and run over to you. As such, while Bolts are a viable option (outdoors and when they still provide good damage), use them to blast things at maximum range. At this range you will probably not see the other players, and hit points will not update accurately, but the monster takes a LOT of angering before it will come hit you.
Simply casting any spell at all nearby a monster will gain it's attention. NPCs in Everquest are omniscient, they know exactly what everyone around them is doing and where they are, and respond with computer reflexes. If you start to cast a spell in hand to hand range of a monster, it will tend to spin and strike you if you are close to the top of the aggro table. Finally, monsters seem to take great offense if you are attacking them with a weapon. Whether this is because it is offensive that you'd try this or due to a quirk in the aggro formulae I don't know, but it is something to keep in mind.
With all these things in mind, you have the basic tools to control the aggro a monster builds and forms against you, and use it to your advantage. But this is all theoretical, I want to give you some practical thoughts and techniques to contribute while you are in a group.
There are two schools of thought for Wizards, two basic patterns for safe and controlled contribution to a group. First is the idea of Controlled Burn, which is the use of lower powered and spaced out spells to continously contribute to the fight without aggroing too much. The second is Second Half Burn, which is waiting until the monster is so totally enraged at the tanks that it will never turn on you, allowing you to unload your most powerful blast on it a few times til it drops. There are advantages and disadvantages to each side, and I want to examine them both.
Controlled Burn
To use this system, you watch the kind of creature that approaches and choose a type of blast that will contribute some without angering the monster too much. This will usually be a spell as many as 2-3 circles lower than the present level of the Wizard, never the most powerful blast. Then the Wizard waits, watching the damage and calculating if you are that good at math, or waiting a set time period such as a count to five, then unloads with another lower powered blast. In this scheme, the most powerful blast a Wizard has is never used except in an emergency or soloing. It has the advantage of visibly contributing for the entire fight, which is reassuring that you aren't an experience sponge in a robe; and it also allows the Wizard to continuously be active, instead of extended time without activity.However it has several disadvantages, being that you almost never get to use your biggest blast (thus feeling neat and powerful), that you have to be patient in that a resist aggros as much as a hit (so if you get a resist you still have to wait the full time before you contribute again), and that your damage will be stretched out over the combat, and thus you will not appear to be doing much.
Controlled Burn requires several kills of a given monster type to learn its aggro patterns and how quickly the tanks will damage and upset the creature. In other words you have to go through several fights to learn how quickly and what spells to use on the monster. Of the two types, Controlled Burn is the most common method used, and is generally the best way to control your mana output and contribution to the group.
Second Half Burn
This system requires the Wizard to watch the monster's life total and wait until it is half or lower life. At that point you stand up, and unload your close to or you best blast over and over, quickly ending the monster's life. This system is very spectacular, it makes the Wizard appear to unload a tremendous amount of catastrophic damage every time. It has the advantage of looking very impressive, of allowing the Wizard to use their best attacks which are always more mana efficient than the lower level ones, and it will make a monster die very rapidly at the point you begin to unload.
However, there are serious disadvantages to this system. First, the hit point total of a monster updates poorly at best, and at any long range is nearly motionless most of the fight. This makes it challenging at best to determine when to begin to uncork on the target. In addition, while the monster certainly has a lot of aggro built up by this point, it is not impossible for it to turn on the caster and begin to vent its displeasure - especially if you get a complete resist or two in the process. Further this uses mana up very rapidly, it is easier to tell when your mana is getting low when you are spacing out your attacks carefully than when you unload in a furious display of power. And lastly, it requires a lot of sitting while people are doing things, which is not only dull but can result in the party thinking you are lazy and unproductive.
Unlike Controlled Burn, a Wizard does not need to have a good understanding of the monster, it just needs to be half dead. It also requires less thought and attention, which is good for someone who had distractions and interruptions in real life, or chats a lot. Second Half Burn is a good choice for someone who is not very subtle or clever, for young people or someone with children who can't concentrate as much. But it has many drawbacks and is not my favorite system.
Sporatic Burn
This is a third system that some use that I feel is very poor. It is to stand, fire off one or two blasts in the entire fight, and sit meditating up to full again without any more contribution. This is the laziest, least difficult system to use, requiring little thought, timing, effort, or knowledge. It contributes little to a fight, although it keeps your mana to full, and makes Wizards look very poor to other classes. I reccomend not using this if you want to be a good Wizard.What Grimstaff Does
I don't like sitting and doing nothing for extended periods of time. While I chose one of the worst classes from this perspective, there are ways to work around this in combat. The continuous burn method allows me to keep doing something through a fight without waiting long periods of times. At level 20, Tishans Clash is one of the spells you get. While this is highly resisted (even with an Enchanter there to help out), it is a very effective tool. I open with this spell whenever possible, and it tends to land safely. When the monster is stunned, it doesn't attack anyone, which is well received by the tanks in the group. It also stops them in their place, which allows you to control when and where the monster stops and is fought. This is somewhat dangerous in that it will rather upset the monster if they resist it (see above for damage plus stun aggro effect), and this works against you.Once this has happened, I will select a given type of blast, usually 1-2 circles lower than the one I am at and wait a moment. If the monster is dying very rapidly, you aren't needed much, fire off a blast and mediate. If it is a normal fight I will cast a spell at the target and wait, usually a count of 3-5 seconds, then trigger off another attack. At this point, stun is usually ready, and I will fire it off as soon as it is. If the monster is still going strong, I'll repeat this process, but if it is almost dead, it is time to sit down and meditate. Once a monster is about 1/4 life or less, it is almost dead and you are not needed, use that time to get your mana back. If the monster is snared it won't even be attacking the tanks in many casts, and casting spells is pointless. Remember, you do not want your party to wait for your mana (most parties wont at higher levels, your mana means nothing to them, only the Cleric's.
If the monster is really tearing the party apart, I will actually use my aggro ability to spread the damage around. I can use a blast or two to pull the monster off anyone, although as I get higher levels the big blasts are so slow it is difficult to use properly in an emergency. If a Cleric is being attacked because of a big heal, you may need to pull the monster off them, use this again. Remember, you aren't made of glass, you can take a few hits, especially with a skin spell up. Take your lumps for the party and save them some trouble or deaths, and they will remember you.