Miss Fortune vs Veigar

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.

If Event Horizon (E) lands around you, stay inside: only the edge stuns, and the cage disappears after 3 seconds.

Get out of the Dark Matter (W) zone as soon as the spell shows: it hurts a lot, but falls from the sky with a delay.

Dodge his spells and deny him kills: with Phenomenal Evil Power (passive), each spell that hits a champion and each takedown gives him power.

Once he hits level 6, don't stay in his range at low health: Primordial Burst (R) deals more damage based on your missing health, peaking below 33%.