A Civil War soldier reenactor naps in his tent.
The good guy can only be as good as the bad guy is bad.
In a mystery, the villain should be hiding in plain sight. The reader wants to solve the mystery before you reveal it. Offer clues to the villain’s identity but don’t forget twists, red herrings, and other suspects to confuse the reader. He shouldn’t know who really did it until the final chapter.
The antagonist must be a worthy opponent in intelligence and ability to the hero. Develop with a back story, motivation, and reason for thwarting the hero. Is it greed, jealousy, or hatred? What made the villain the way he is?
The villain makes life hard for the hero and makes the hero more interesting.
Play both with and against type by contrasting good and evil in both the hero and villain.
What role does the antagonist play in the hero’s decisions and does his influence grow toward the end?
Make the crime fit the villain – he must have expertise and be capable of executing the crime.
Does the antagonist have any phobias, weaknesses, or shortcomings?
What redeeming qualities, skills does the villain have?
The villain justifies the crime by righting a prior wrong, revenge against a perceived enemy who deserved to die, vigilante justice because system didn’t work, protecting a loved one, or restoring order to the world.
The antagonist can be sympathetic to the reader but justice must prevail.
A story needs quirky friends or family to add interest to the “normal” main character.
An adversary isn’t a villain but causes trouble for the hero. He’s a good guy who drives the sleuth nuts, pushes his buttons, torments him, puts obstacles in his path, and is a pain in the butt. They create spice and make other characters come alive. They can cause all kinds of interesting problems and complicate the story by throwing up roadblocks.
An adversary thwarts, annoys, and generally gets in the protagonist’s way. He reveals the characteristics of the hero through arguments, physical and mental struggles, and by revealing good and bad traits toward the adversary. Think of Dr. Watson to Sherlock Holmes or Lulu to Stephanie Plum.
A female hero like Stephanie has a complicated love life because her character’s problems rely on her being a single woman.
Other female characters can be happily married but the husband is in the background or a partner.