Summarize this article:

The best villains seem to enjoy their cruelty. To embrace your most evil laugh, make like them and try on a crooked smile. The less this looks like your normal smile the better: It can be unnervingly big, small or toothy. The point is to look a little demented and crazy. Practice in front of a mirror to find out what crazy smile you like best. Furrowed brows make you look calculating and sinister. For the best look to go with your evil laugh, lower your brow as if you are hatching an evil plot. You can also lower one brow and raise the other to make yourself look a little off. The more you can unnerve others the better. Try gesturing with your hands to enhance your evil laugh. Depending on the character of your laugh, you can try a calculating gesture, such as palms facing one another with your fingers drumming together, or go really crazy and just reach up to the sky madly with outstretched fingers. Either way, incorporate your arms to enhance your evil aura.

Summary:
Crack a maniacal smile. Furrow your eyebrows. Gesticulate wildly or try calculated hands.