My english is bad but i try to show you guys my build that work great for me, maybe great for you too.
I use Gear that increased my Attack Speed, Skill Damage and Life Regen sometimes i use gear that increased my attack dmg (but i dont know if that have effect on life steal).
HEDRONIC SIPHONING: A portion of damage dealt by Hedronic Arc is returned to Attikus as health. +15% Life Steal
INVIGORATING POUNCE: Pounce gives Attikus life steal on all damage dealt for a short time. +30% Life Steal for 8 Seconds
BRAWLER’S BOON: A portion of damage dealt by Attikus’ melee attacks is returned to him as health. +15% Life Steal
QUICKENING ARC: Attikus moves faster while Hedronic Arc is shocking enemies. +30% Movement Speed
HEDRONIC REGENERATION: Attikus gains a small boost to health regeneration for each charge accumulated by Hedronic Collector. Up to +35 Health Regeneration Per Second
CHAIN BREAKER: If Pounce kills a major enemy the skill’s cooldown is immediately reset.
SWIFT STRIKES: Increases Attikus’ attack speed. +20% Attack Speed
POWER POUNCE: Increases Pounce’s damage +15 Damage
GREASED LIGHTNING: Increases the damage per second dealt by Hadronic Art but reduces its duration. +100% Damage per Second, -2 Seconds Duration
WAKE OF DEVASTATION: Hedronic Eruption scorches the earth, dealing damage over time to enemies in its area of effect. +240 Damage over 2 Seconds.
I know this Build/Guide is not the best but i hope it help you guys to have fun with Attikus.
Here is a short video from me playing Attikus hope you enjoy: Attikus Youtube