Katarina vs Locke

Pick up your daggers in trades and teamfights: Voracity (passive) then hits every nearby enemy, and each dagger picked up lowers the cooldown of Shunpo (E).

After Bouncing Blade (Q), blink to its dagger with Shunpo (E): it lands behind your target, and picking it up triggers Voracity (passive).

In teamfights, hit as many champions as you can before they go down: when one of them dies, Voracity (passive) sharply lowers all your cooldowns.

Cast Death Lotus (R) once the enemy CC is used: it's a channel, and a single CC is enough to cancel it.

Back instead of staying in lane at low health: Silver Stake (passive) adds damage to his autos that grows with your missing health.

Trade after Ashen Pursuit (E): it's his only instant movement, and its 10-second cooldown only resets if he gets a takedown.

During Soul Ignition (W), only hit him if you can kill him: at the end, he heals back part of the last damage taken, yours included.

Marked by Purgatory (R), stay above its threshold: if you have a heal or a shield, use it, because he seals marked enemies who drop below it.

If the Purgatory (R) artifact lands, hold the area where it fell: by picking it up, Locke raises his execute threshold for each sealed champion, for the rest of the game.