Thresh vs Nami

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.

Change direction when she casts Aqua Prison (Q), then step up if she misses: it's her only stun outside her ult, on a 12 to 8 second cooldown.

Avoid trading when she casts Tidecaller's Blessing (E) on her ally: their next autos and abilities slow you and deal more damage.

Step out to the side of Tidal Wave (R): it travels a long way but moves slowly, and its slow lasts longer the more distance it has covered.

If you can engage, target Nami when she steps up: with no dash or leap, she can only walk away.