AlimNassor said:
Err, how do people learn to raid properly? Every guild/party i've been in boots me if I mess up. Why do people get so angry when your damage isn't amazing?
Watch videos of fights, read strategy guides, ask knowledgable questions in raid before the fight if you're not familiar with which strategy will be employed.
Be sure you know what specific things you're expected to do! If you're a DPS you may be expected to move in or out of various things or interrupt casts in addition to doing damage. Keybind with these things in mind, and setup a UI that makes it obvious when things like casts are going off.
Install DBM or Bigwigs, they are a huge crutch for raiding and trivialize a lot of stuff that's supposed to be hard.
Use sites to help you gem and enchant, like
http://www.askmrrobot.com/wow
Use sites to help you learn the best spec/glyphs/rotation, like
http://noxxic.com/ (This site isn't 100% accurate but I find it a lot easier to browse here than EJ when I just want to be semi-competent on alts I haven't played in forever.)
Look up gear upgrades, go after ones that are decent for you that you can get solo. (Crafted or bought stuff.)
Best of all find a group of friends willing to carry you through a couple raids until you learn the ropes.
Maybe that sounds like a lot, but it doesn't actually take that long to learn a rotation and fix your glyphs or gems. That's where people fail a lot, most often.