For optimal burst, try to combine Relentless Pursuit into Piercing Light.
Ardent Blaze actually explodes in a star pattern. Try to line it up so the spokes hit enemy champions.
Once you have chosen an angle for The Culling, you cannot change it. Pick your moment well!
Because of Lightslinger, Lucian benefits more from Attack Damage than he does from Attack Speed.
Lucian has strong burst, but little sustained damage.
Lucian cannot change the aim of The Culling. Take advantage of this by avoiding the angle of the bullets.
Piercing Light does not give Lucian extra Attack Range. He still needs to find a target in range to line up his shot. Avoid Piercing Light by anticipating the angle Lucian will choose.