To write the perfect villain you must make your villain believable. This means the reader must understand what motivates your villain. Why the villain behaves the way they do. The motives behind why your villain feels justified with his actions have to be explained.
It is not enough for your villain to just be mean and evil. When you show your readers the villain’s logic through the villains POV, (point of view) be sure to remember you are in the villains head, and thus villains do not see themselves as evil. Villains believe their actions are justified and you must explain why. By doing so you will increase the suspense in your story, and the uncertainty of your plot will hopefully keep your readers attention.
Be sure to show your villain from your hero and heroine’s POV, so readers can see how mean and threatening your antagonist actually is toward your main characters.
Most importantly, make your villain a worthy adversary. This strengthens the main characters when they prevail over evil.