Vladimir vs Nasus

After two Transfusion (Q) casts, the next one is empowered for a few seconds: save it for a trade, since it hits harder and heals you based on your missing health.

Last-hit minions with Transfusion (Q) until your items come in: it deals damage before healing you, and costs you nothing.

Charge Tides of Blood (E) for at least 1 second before releasing: the missiles then also slow, and their damage grows with the charge.

Save Sanguine Pool (W) to dodge CC or a burst: for 2 seconds, you're untargetable. It costs you part of your current health.

Cast Hemoplague (R) before your burst: infected enemies take increased damage from all sources, then the blast heals you for each champion hit.

Early on, take a trade whenever he steps up to last-hit a minion: each kill with Siphoning Strike (Q) increases its damage for the whole game.

Freeze the wave near your tower: to farm with Siphoning Strike (Q), he then has to step up and expose himself to ganks.

Once he hits level 6, don't engage during Fury of the Sands (R): for 15 seconds, he gains health and resistances, and his area damage scales with your max health.

In teamfights, if you're ranged, hit him while backing off: he has no dash, only Wither (W), a slow that grows stronger over time.