Mel vs Sivir

Stay back and poke with Radiant Volley (Q): its projectiles explode in an area up to 950 range, and each hit applies Overwhelm.

Land an auto after each spell: Searing Brilliance (passive) adds three projectiles to it per spell cast, and enough Overwhelm executes the target.

Save Rebuttal (W) for a dangerous projectile: the barrier sends it back to its caster, and you gain a shield and move speed.

Hit your target head-on with Solar Snare (E): only the core of the orb roots, the aura around it just slows and damages.

Cast Golden Eclipse (R) to finish from range: it hits every enemy marked by Overwhelm, wherever they are, harder with each stack.

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.