Fizz vs Yasuo

Last-hit minions with Seastone Trident (W) early on: if the empowered auto kills, you get mana back and its cooldown drops.

Save Playful (E) to dodge a key spell: you're untargetable for 0.75 seconds, then land with damage and a slow.

Cast Chum the Waters (R) from range: the farther the fish travels before it attaches, the stronger the shark's slow and damage.

After Chum the Waters (R), chain Urchin Strike (Q) and Seastone Trident (W) while the target is slowed: the shark then bursts up under them and knocks them into the air.

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.