Miss Fortune vs Vel'Koz

Fire Double Up (Q) at a dying minion in front of a champion: if the shot kills the minion, the bounce onto the champion always crits.

Switch targets often: Love Tap (passive) adds damage on each new target, and lowers the cooldown of Strut (W).

Activate Strut (W) to get in position before Bullet Time (R): you instantly gain its max move speed bonus, plus attack speed.

Cast Bullet Time (R) on enemies who are CC'd or bunched up in a chokepoint: it's a channeled cone, and each wave can crit.

Get out of the line of Plasma Fission (Q) and watch its sides too: the bolt splits into two branches at 90 degrees when it hits a target or he recasts it.

Back off after taking two of his spells: at the third Organic Deconstruction (passive) stack, you take a burst of true damage.

If you can engage, go in after Tectonic Disruption (E): it's his only spell to push back someone charging him, and he has no dash to escape.

If you have a stun, a silence or a knock-up, save it for Life Form Disintegration Ray (R): any of them interrupts the ray.