In almost every instance in wow, you'll have at least one noob with you who constantly gets aggro from the mobs. This noob has usually rolled a noobish class like warrior, paladin, druid or - Light help you - death knight, and he probably thinks he's some kind of “tank” or something.
Obviously, you must save this noob from the dangerous mobs in the instance. This guide explains how to prevent him from being hit by the mobs, so the party can successfully complete the instance.
Part 1 – The pull
The noob will regularly be the first to aggro a group of mobs, often by using a ranged ability. Such behaviour can not be allowed, and should be stopped.
The best way to stop it is to nip it in the bud. That's why you should always try to attack mobs before the noob does. Hit them with everything you've got before he gets the chance to attack. Using abilities like multi-shot, which hit multiple mobs, will make it virtually impossible for him to get aggro on all of the mobs, and your party will be safe.
Should the noob get in an attack before you do, don't worry. Abilities like fireball, charge and cheap shot can still save the day. Just be sure to hit the mobs that are running towards the noob before they reach him, and pull them as far away from him as possible. You get extra points for breaking a dangerous group of hard-hitting mobs into pieces, spreading them out across the area so the noob can not possibly reach them all.
Sometimes, the noob will try to pull a caster mob. Realizing he cannot possibly win a fight against a caster mob, he will move back around a corner, out of the line of sight of the caster mob. What the noob probably doesn't know is that the caster mob will just run after him, around the corner, and start attacking him again. To prevent this from happening, you should immediately lay the smack down on the caster mob with your ranged abilities. That way, the caster mob will target you instead and stay in place, far from the noob.
Part 2 – The fight
Sometimes, the noob will manage to get aggro on a whole bunch of mobs, who will all start hitting him. Don't worry, not all is lost just yet. You can still save the noob. The most important thing is that you start doing as much damage as you can immediately – don't give the noob a chance to foolishly build threat on all mobs. As soon as the fight starts, use your highest-damage abilities. If the noob misses his first attack or two, chances are that you can still manage to pull aggro away from him.
It is also important that you target a different mob than the one the noob is targeting, since that one will be the hardest to pull aggro on. Use /assist to see the noob's target, then pick a different one yourself. If the group you are in is using marks, never, ever, attack the mob marked with a skull. Usually, the mob you will have to attack is marked with a moon or a blue square instead.
When you successfully manage to get aggro off the noob, make sure to run away from him as quickly as possible. Put some serious distance between him and you, so he doesn't unintentionally use a taunt ability on your mob. After all, it's your mob, not his.
In instances where mobs run away when they get low health, make sure that your party burns down the health of several mobs at once. That way, it will be nearly impossible to stop them all for the noob and the others in your party, so as they run away they will aggro more mobs, which means you will finish the instance quicker.
If you are in a team with a warrior or druid noob, keep an eye on the red bar below next to his name. The more he hits and gets hit, the fuller this bar gets. Your goal is to keep this bar as empty as possible. The emptier the bar is, the less threat the noob can generate, and the mobs will move to more appropriate targets like you and the healer instead.
If the noob is a paladin, he will have a blue bar instead. This bar will be full at the start of fights, and grow empty as the noob does foolish things. If the noob gets healed, though, it will get a bit fuller again. That's why you should make sure you are the one taking damage instead of the noob. That way, his blue bar will go empty really quickly, and he will not be able to do any more foolish things.
If the noob is a death knight, he will have a light blue bar. This bar bounces up and down from empty to full and back again, and there seems to be little correlation between the bar and the noob's threat level. This unpredictability makes protecting a death knight a real challenge. Let's hope you're up to it.
Part 3 – Party etiquette
Teaming with a noob can be a frustrating experience. These noobs not only steal your aggro, they also steal the heals that you need to stay alive and do your imba dps. So, the moment you get hit, you should start reminding the healer that you need heals. Spamming “HEAL ME!!!” in party chat is a good way to do this. Even better is spamming it in raid warning. That way, it will appear right in the middle of everyone's screen, and the healer will have no choice but to heal you instead of the noob.
Likewise, if you are so unfortunate to die, it is a good idea to spam "REZ ME!!!", "REZ PLX" or simply "RES" until someone resurrects you. This is important because, if you died, the noob probably died too (as there was no one to save him) and so he will surely run and ruin everything again if he is resurrected before you are. There is always a chance that the entire group died, which means there is no one to resurrect you, but it'd still be wise to spam "RES" so the healer knows who to resurrect first when he/she returns after corpse-running back to the instance. Also notice that you must never release your corpse when you are dead, instead of waiting for someone else to come and resurrect you. This is because your corpse acts as a arrow on the minimap, which will help the rest of the group to return to the same place in the instance before the group died and not get lost while trying to find this. Spamming "REZ ME!!!" during this time often also acts as motivation to the group, as it shows you are still online and willing to continue the instance even after dying.
It is also important to keep the noob in his proper place. The best way to do that is to repeatedly ask if anyone has damage meter installed, and ask to have it posted after every fight. Make sure to laugh at the noob and the healer if they're below you in damage, and call them noobs. This will force them to respect your leet skillz. This is also very motivational as it encourages players to improve their skills, even though they would never match yours.
In some groups, the noob will ask if you have KTM or Omen installed. If the noob does that, be sure to insult him, and tell him that only noobs need addons. If he questions you, ask another party member to post the damage meter stats, and point out how much better you are.
Of course, the real reason you're doing instances in the first place is phat lewt. To make sure that you get the phattest lewt, make sure to loot mobs as quickly as possible, especially when you're still in combat. That way, any greens, blues and purples will pop up on everyone's screen while they're still fighting, which will obscure their vision of the fight but increase their morale.
Also, make sure to roll need on everything you can possibly use, even if it doesn't fit your class or spec or you already have better gear. You deserve it – you saved the party from the noob, so you should get first pick of any drops. It's only logical. If the noob is being difficult and begins criticizing you or even demands some of the loot, either be honest and tell him he is a noob who should be thankful you saved him or end the argue with a simple explanation such as you needing the lewt for your off-specc or money.
Finally, and most important of all, always leave during the middle of an instance. This will make it clear to the rest of the group just how important you are. It signalizes that you are a very powerful and skilled player which many other players need to help them, and therefore rarely have the time to complete a instance. Be sure to explain this fact to the group by saying "sry gtg friends need me" or "guild calling". Stating this, the group will notice how skilled you are, and will for sure invite you to groups later. For added effect, pull some mobs right before you leave the group, to show that you would still want to continue the instance unless you had to leave. The others will be in awe of your greatness.