Nasus vs Irelia

Last-hit minions with Siphoning Strike (Q): each kill with the spell permanently increases its damage, by more on large minions and champions.

In teamfights, cast Wither (W) on their carry: the slow grows stronger over the spell's duration and also reduces their attack speed.

Cast Fury of the Sands (R) as you enter a teamfight: for 15 seconds, you gain health and resistances, damage nearby enemies, and Siphoning Strike (Q) comes back faster.

Early on, farm rather than force trades: Siphoning Strike (Q) stacks are permanent, and every minion you last-hit makes you stronger later.

Don't stand near your low-health minions: Bladesurge (Q) resets when it kills, so she chains dashes from minion to minion until she reaches you.

As soon as the first blade of Flawless Duet (E) lands, change direction: the stun only hits enemies caught between the two blades.

Take your trades when Ionian Fervor (passive) isn't stacked: she builds stacks with her abilities, and at max stacks her autos deal more damage.

Save your burst for after Defiant Dance (W): while charging, she takes much less damage, but she can't do anything else.

Dodge Vanguard's Edge (R): its blades make you Unsteady, which resets Bladesurge (Q) on you, and the cage they form damages and slows anyone who crosses it.