Aurora vs Garen

Poke with Twofold Hex (Q), then recast it once the target has lost health: the hex passes back through them and deals more damage the more health they're missing.

Cast Across the Veil (W) to dodge a skillshot or break a chase: you leap and turn invisible briefly, and a takedown resets its cooldown.

Cast Between Worlds (R) in the middle of grouped enemies: those trying to enter or leave the area are slowed, which keeps them under your team's spells.

Inside Between Worlds (R), teleport from one edge to the other to dodge skillshots and reposition, as long as the area lasts.

Hit him regularly, even with a small poke: Perseverance (passive) only regenerates him if he hasn't taken damage recently.

If you're ranged, kite him: his kit has no dash, and only Decisive Strike (Q) speeds him up and removes his slows.

Wait for the Courage (W) shield to end before your burst: the spell starts with a shield and tenacity, then keeps only a damage reduction.

Once he hits level 6, back instead of staying in lane at low health against him: Demacian Justice (R) deals true damage that grows with your missing health.