This isn't a rant. I just want to help people making critical mistakes and save all of us some debt.
1. Don't rush it.
Take it one mob at a time if you have to. Stay behind your tank unless you're a scout type. Re-spawns in tight quaters suck.
2. Stay with your party.
Don't wander off. One person getting attacked three rooms away will send the group (at least a tank or healer) into a panic to save the stray member. This will only result in a complete wipe or near wipe. Also, if someone does happen die away from the group, make sure the whole group goes back to get the shard. Chances you'll run into re-spawns or "trained" mobs.
3. Listen to group members who are familiar with the zone.
Sometimes they are bossy a$$holes, but if they seem to know what they are talking about, its your best chance at success. Tough it out, get your exp or your quest, and curse them later.
I hope this helps and I don't seem like one of those "bossy a$$holes".
:)