Zeri vs Sivir

Aim each Burst Fire (Q): it's your main attack, reaching 700 range and hitting the first enemy in its line.

Aim Ultrashock Laser (W) at a wall: the pulse becomes an area laser that slows and critically strikes champions.

Aim Spark Surge (E) at a wall: you vault over it, much farther than with the dash alone, and your Burst Fire pierces for a few seconds afterward.

Cast Lightning Crash (R) near a champion: hitting them gives you attack speed and move speed, and each hit on a champion extends the effect. Attack while backing off.

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.