Garen vs Yasuo

Trade with Decisive Strike (Q), then Judgment (E), and back off: the Decisive Strike silence stops your opponent from answering with spells.

During Judgment (E), stay closer to your opponent than to their minions: the nearest enemy takes extra damage.

After a trade, back off until Perseverance (passive) kicks in: without recent damage taken, you regenerate part of your health every second.

Activate Courage (W) just before the bulk of the damage: you first gain a shield and tenacity, then a longer damage reduction.

Save Demacian Justice (R) to finish: its true damage grows with the target's missing health.

Hit him with a cheap attack to trigger the Way of the Wanderer (passive) shield, then start the real trade: otherwise, it absorbs your best damage.

If you have projectiles, save them for after Wind Wall (W): it blocks them all for 4 seconds, on a 25 to 17 second cooldown. Other spells go through it.

Don't stand right behind your minions: each one gives him a target for Sweeping Blade (E), and he gets closer to you with every dash.

Get out of the line of his whirlwind, the third Steel Tempest (Q): without a knock-up, he can't cast Last Breath (R).

Judge his threat by his crit items more than his level: Way of the Wanderer (passive) raises his critical strike chance, so each crit item does more for him.