Samira vs Sivir

Vary your hits to build your Style: Daredevil Impulse (passive) only counts attacks or spells different from the previous one, and your ult needs an S rating.

Go for the enemies your allies immobilize: Daredevil Impulse (passive) makes you dash into range, and extends the knock-up of an airborne enemy.

Dash through a minion or your target with Wild Rush (E): if a champion you damaged dies within 3 seconds, the cooldown resets.

Save Blade Whirl (W) for a projectile that matters, like Ashe's ult: the whirl destroys enemy projectiles that enter its area.

Cast Inferno Trigger (R) in the middle of several enemies: 10 shots in 2 seconds on everyone around you, with life steal.

Dodge Boomerang Blade (Q), then its return: it damages on the way out and on the way back, and it costs Sivir a lot of mana.

If you have CC, cast a cheap spell first, or fake a step forward: Spell Shield (E) only blocks one ability, and heals her if it blocks.

Back off when she casts On The Hunt (R): her whole nearby team gains move speed to engage on yours.

Don't leave her alone on a lane for too long: with Ricochet (W), her autos bounce between minions, and your wave, then your tower, fall fast.