This stat can be increased through Equipment that have the proper Runes, and specific Trinkets.
The table below shows amount of Damage added based on Value of Strength for a rogue.
|Amount of Strength (10 base + X)||Resulting Damage Increase|
This means that every point of Strength increase Damage by about 0.7 for rogues. Remember to include agility for rogues since it effects damage also.
For warriors they get a larger damage from each point of Strength.
Amount of Strength (12 base + X)
Resulting Damage Increase
So warriors will gain 1.7 damage per point of Strength.