Primary Attacks (attacks with your chosen weapon, for example Soldier's Sword) generate Energy (blue bar under the players health bar).
Power abilities will trigger when you have full Energy.
Energy is gained not on attack, but on enemy hit,
investing in the following stats will therefore increase the rate at which you generate Energy, & thereby how often you activate your power abilities:

• Attack Speed
  
• Instant Attack Chance

Focusing on Energy generation in this manner is crucial for this build to work properly.

Race: Human
Class: Barbarian
Origin: Cult Initiate
Weapon: Soldier's Sword x2

(roughly in order of importance)

• Giant's Reach
  
• Resilience
  
• Primal Strength
  
• Bloodthirst
  
• Rampage
  
• Berserker Rage

• Primal Roar

• Whirlwind

• Band of Primal Power
  
• Edge of Darkness

• Blade Dash