Hwei vs Sivir

Poke with Devastating Fire (QQ) in lane: the fireball explodes on the first enemy hit and adds damage based on their max health.

Hit the same champion with two damaging spells: Signature of the Visionary (passive) then leaves a signature beneath them that explodes shortly after.

Pick the subject that fits the moment: Devastating Fire (QQ) for damage, Pool of Reflection (WW) to protect your allies, Crushing Maw (EE) to pull a group together.

Block a chokepoint with Molten Fissure (QE): the line of eruptions leaves pools of lava that slow and damage enemies.

Cast Spiraling Despair (R) on a champion surrounded by allies: the vision expands around them, slowing harder and damaging nearby enemies before it explodes.

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.