Set everything to smart cast, including all item slots. Clicking is wasting valuable time you could be using smashing the keyboard in a mad dash to get everything off in 1.5 seconds.
Set smart cast to range shown smart casting and practice e stuns with it until the circle is burned into your retinas. Then remove it because 360 no hud e stun all skill dubstep montage.
Practice not flailing on the keyboard when you land a stun and get used to dfg > w > r > q combo or dfg > q > w > r > q combo for the REALLY big fuckers.
Acquire Superb Villian Veigar skin, because the stache is legendary. Proceed to get ALL the bitches.
That is how you play veigar.
Oh ya, and farm with q all the time, because free chalice as passive and stack ap, fuck bitches.