The factors affecting the damage per second (dps) of "World of Warcraft" hunters are talent point allocation, pets, pet talent point allocation, glyphs, gear and rotation. Rotation -- the abilities you choose to use and the order in which you use them -- is the most complex of these factors and takes the most player skill. Upgrading your gear is mainly a matter of running random dungeons until you have adequate gear for raiding.
Pets, Talents, Glyphs and Rotation
Choose a marksman or survival talent tree for your main spec. Although beast mastery does high burst damage, it generally has lower sustained dps than the other two trees for raiding.
Select only those talents that directly increase dps or focus regeneration. Don't worry about survivability or crowd control talents. In dungeons and raids, mobs should be hitting the tank, not the hunters, and healers are responsible for your health. Your main job is dps and you have good crowd control even with pure dps talents.
Use a ferocity or cunning pet with pet talents optimized for dps. Tenacity pets are best used exclusively for solo questing. In instances, use a pet that brings important buffs or debuffs to your group.
Use the must-have glyphs for your spec. Marksman hunters should use glyphs of steady and arcane shot. Survival hunters need explosive shot, serpent sting and either arcane or kill shot. Beast mastery hunters need kill command, arcane shot, bestial wrath and either kill shot or serpent sting. Most hunters of all specs use disengage and feign death as well.
Be aware that the optimal rotation for hunters is different for each spec and also depends to a degree on your gearing. Blizzard is constantly making slight changes as well. You will normally use "aspect of the hawk," have "hunter's mark" on your target and keep up one dot (either serpent sting or black arrow) depending on spec. Kill shot should be used whenever it is off cooldown. Marksman hunters use chimera, aimed, steady, cobra and arcane shots in their rotations. Survival hunters use explosive, cobra and arcane shots and beast mastery hunters use focus fire, kill command, arcane shot and cobra shot.
Use gear with agility. Agility is the only primary stat that matters for hunters. Strength, intellect, stamina and spirit are useless for a PvE hunter. Gem and enchant for agility whenever possible.
Stack hit to the hit cap. Hit rating determines the chance that a shot will miss a mob, and misses dramatically lower your dps. The "hit cap" is the point at which your shots will never miss, and stacking hit over this cap is worthless. Choose crit, mastery and haste for secondary stats. Ignore expertise, defense, dodge, armor rating, parry, spellpower and mp5.
Reforge secondary stats according to your spec after you have reached the hit cap. For beast mastery, survival and marksman hunters, crit is your best secondary stat.
Choose a ranged weapon with the highest possible dps rating. Hunter dps is extremely dependent on ranged weapon dps. Choose melee weapons for agility and secondary stats; a skilled hunter never actually hits anything with a melee weapon.