Thresh vs Milio

Open with Flay (E) before Death Sentence (Q): the slow makes the hook much easier to land.

In lane, space out your autos: Flay (E) charges them passively, and the longer you wait between two autos, the more damage they deal.

Don't recast Death Sentence (Q) on reflex: the target is already being pulled toward you, and jumping on them often exposes you for nothing.

Throw Dark Passage (W) toward an ally in trouble before they need it: they can click it to come back to you, with a shield.

Place The Box (R) right after a successful hook: to escape, the target has to break a wall, and the first wall broken slows them and deals full damage.

Dodge Ultra Mega Fire Kick (Q): it knocks you back, then explodes behind you and slows you.

Back off when Cozy Campfire (W) follows his carry: they gain attack range and restore health over time.

If your team has several CC spells, save one for after Breath of Life (R): it cleanses disabling and immobilizing CC from his nearby allies.

If you can reach him, go for Milio first, especially away from his allies: he has no dash or leap, and without him, his carry loses shields, heals and range.