Attribute

There are various attributes that are ascribed to classes, weapons, and armor. All affect how a character performs in the game; some attributes are more valuable to one class than another.

Agility
Agility contributes to 50% of the DPS for Rogues and Hunters and Strength contributes to the other 50%. Agility will enhance the chance to score a critical melee hit for all melee classes.
 * Increases your attack power with ranged weapons.
 * Increases your armor.
 * Increases your chance to score a critical hit with a weapon.
 * Increases your chance to dodge attacks.
 * Rogues gain a much stronger bonus to dodge from agility than other classes.
 * Hunter & Rogue: Increases your attack power with melee weapons.

Intellect

 * Increases the rate at which you learn weapon skills.
 * Increases your Mana points.
 * Increases your chance to score a critical hit with spells.

Spirit

 * Increases health and mana regeneration. Spirit affects all characters' mana and hit point regeneration rates in and out of combat.

Stamina

 * Increases Health points.

Strength
Strength does not affect critical hit chances at all. Strength does not improve your chance to block, but rather the amount blocked when you succeed. This amount is determined in part by Strength (and the other part by your shield). Strength will contribute to 100% of the DPS for all classes other than Rogues and Hunters.
 * Increases your attack power with melee weapons.
 * Increases the amount of damage you can block with a shield.

Weapons
Your total damage output when fighting with two weapons should be higher than fighting with one weapon and a shield, but roughly equal to fighting with a two-handed weapon. Off-hand attacks deal 50% of the weapon's designated damage. Therefore, it's wise to always put the best "damage dealer" weapon in the main hand.
 * Attack (AR) - Attack Rating.
 * Power (AP) - Attack Power.
 * Damage (DMG) - Weapon Damage.

Armor

 * Defense (AC) - Defense Rating.
 * Armor - Physical Damage Reduction.