Know who you play with, learn how your guildmates behave and learn to have a synergy with them. Having a special channel for each separate group helps, like fluxmelee, fluxheal, fluxtank, fluxranged and so on, where you can discuss specific aspects of the game that most of other players don't need to know or care about.
This way communication is clearer and we can discuss only important stuff or simply troll on voice chat (yay).
- don't stand in fire
- intrerupt spells of mobs (coordinate with others if possible)
- stun mobs if possible, this helps tanks and healers a lot
- learn your DPS rotation and best stats in order to not deal less damage than a tank
-use your damage taken reduction cooldowns periodically when taking damage is iminent
-know how to kite mobs, slow/stun them/root them too if needed
-volunteer to dispel debuffs on the raid, help those healers out, in the end, a GCD wasted from a healer for a dispel can result in a death, in your case it's just 0.01% of the boss's HP, you do the math
-you really have no excuse to stand in "stuff" as a ranged , on the contrary, you can help when the raid takes intensive aoe damage with cooldowns that reduce your of the raids's damage taken
-do not overheal, nobody likes healers being out of mana after 30 seconds
-coordinate who heals what, read the intro about class channels
-dispel debuffs ask for the DPS to help if it's an intense healing fight
-don't stand in "fire" cancel your cast even if x or y will die in order to save your own life, that extra heal won't help if you're dead at the end of that cast
-learn to use instant heals while you move too
-if you are chased by a mob, root it/stun it/fear it or call out for help
-if it's a low heal demanding fight, drop a DOT or cast a spell at the boss too, I've seen too many wipes at 1% to ignore this part
Tank's job is usually simple, that is if you are a shitty tank.
Being the cool kid on the block here requires a lot of skill and intellect because:
-you need to learn where to position mobs/bosses in order for the rest of the raid to position safely and faceroll away
-if mobs knockback, make sure you stay with your back against a wall
-taunt stuff off the raid
-coordinate with the offtank and assist each other in order to take less damage
-if there are 100 trash mobs on you, don't be brave and take a beating to Valhalla, learn how/when to kite or run away from them
-if a boss/mob is tauntable, and shit hits the fan, you and the offtank can stay away from each other and ping-pong the faker in order to squeeze in some extra seconds.
-if boss cleaves/use breath/tail swipes know that stuff and try to position it properly
-if a mob or boss enters a phase or moves to a location to do stuff, WAIT for him in the same spot and he will come to you after he finish his stuff, no need to follow him then slowly drag him back to the initial position, you basically mess up 20 other people's positioning with your fancy stuff