Author Ellen Jackson took part in a chat about writing villains hosted by the Institute for Children’s Literature. Here’s part of what she said:
“Give the villain a physical trait or two that are unpleasant, such as: an unpleasant voice that's sharp, cruel, harsh, raspy, a hyena-like laugh, a sinister odor, eyes that stare, that are pale, cadaverous, sinister, cold, like slits, narrow, yellow, staring. Have him or her speak too precisely or pedantically. He might be cruel, merciless, shrewd, mesmerizing, vengeful, a bully, cunning, sly, conniving, etc.”
Read the whole transcript here.