Ezreal vs Samira

Land Mystic Shot (Q) as often as you can: each hit lowers all your cooldowns and adds a Rising Spell Force (passive) stack.

Detonate Essence Flux (W) with a spell rather than an auto: the orb deals its damage either way, but a spell refunds its mana cost plus a bonus.

Save Arcane Shift (E) to escape unless the kill is certain: it's your only way to reposition, on a 26 to 14 second cooldown.

Cast Trueshot Barrage (R) across the map to finish a fleeing target: it hits everything in its line, but deals less to minions and non-epic monsters.

Take a trade once Wild Rush (E) is used: it's her only dash, and it only comes back if a champion she damaged dies within 3 seconds.

If you have projectiles, wait for Blade Whirl (W) to end: it destroys those that enter its area, but not spells without a projectile.

Back off when she chains her hits: each one that differs from the last builds her Style, and at an S rating, Inferno Trigger (R) shoots every enemy around her.