Damage dealers, as the name implies, are players who are responsible for dealing damage in the group. It is almost always abbreviated as DPS or DPSer in-game. Their importance should not be neglected because without reasonable DPS, it may take a long time to kill mobs.
Primary function of DPS
The primary function of DPS is dealing damage to the mobs. Good damage dealers help the group to run smoothly by killing the mobs in a short time. Running instances with a group full of bad DPS means prolonged time will be needed for the fighting and completing the instances.
Mana management is important for mana-using DPS classes. No mana can mean no DPS for some!
A dead DPS produces zero damage. To maximize your total damage output, the importance of staying alive cannot be emphasized enough.
First of all, make sure you have reasonable health for the particular fight. This is especially important for fights that everyone is certain to receive some damage.
Second, walk out of danger ASAP. Many bosses have AOE abilities that do high damage. Melee (and sometimes caster/ranged) DPS need to learn what graphic to look for and run out immediately. Make sure you run out of it right away, even if this means canceling a spell you are casting.
Third, don't be cheap and drink a healing potion if your health goes too low. Sometimes your healers may be busy enough at healing elsewhere.