Your total weapon damage is damage shown on the weapon + damage gained from AP
How do I gain AP?
- 1 Strength = 2 AP for Warrior, Paladin, Druid
- 1 Agility = 1 AP for Rogue and Druid
- 1 Agility = 2 AP for Hunter
- Raw AP on items
Note that Strength and Agility get boosted by blessing of kings, while raw AP does not. So on alliance the attributes are worth more.
How much is AP worth? The simple rule is 14 AP = 1 DPS. So with a 3.0 speed weapon you get +3 dmg per 14 AP. So the formula for your:
total weapon damage = base weapon damage + (AP/14) * weapon speed
Example: You have 700 AP and a weapon which deals 100-150 dmg at 2.0 speed. 700 AP is 50 dps, so +100 dmg at 2.0 speed, so your total weapon damage is 200-250.
One more thing:
Most instant attacks are normalized, e.g. sinister strike, backstab, mortal strike. This means they ignore your weapon speed and instead treat every weapon with the same speed (1.7 for daggers, 2.4 for other 1h weapons, 3.3 for 2h weapons, 2.8 for ranged weapons). This was done to reduce the advantage slow weapons had over faster ones. Slow weapons are still better due to their higher base damage and windfury, but not as much as before normalization. Do note that paladins Seal of Command and shamans windfury are not normalized at all, so slow weapons are preferable here. Slam is also not normalized, so would prefer a slower weapon.
Battle shout is a simple AP buff, so you can just add it to the above calculation. Death wish as a percentage bonus happens after everything else. So with our example above, death wish boosts it by 20%, so you'd end up with 240-300 damage.