Every good story has obstacles. Sometimes those obstacles are other people. Creating a good villain takes time and thought – just like a good hero. Developing both requires answering many of the same questions: What do they want? Why? How will they get there?
After you’ve put in work creating a worthy protagonist for your story, you should do them justice by giving them a worthy enemy. A living (or dead) villain has thoughts and a personality just like your protagonist, and it’s up to the writer to decide what those are.
What is the prize for your villain? Everyone wants something, even (especially?) the bad guys. Whether it be a physical prize, the destruction of the protagonist, or an artisanal bagel, there needs to be a reason your villain gets up in the morning on puts his bad boots on.
Motives, desires and goals are what drive most people in waking life and the characters we create on the page should have them as well. Villains are villains because their goals go against the goals of the protagonists. What are your villain’s goals?
What led up to this? Why does your villain want what he or she wants and how did they get into this current situation you’re creating? Even if you don’t plan to relay information to your readers, it’s a good practice to have all the answers yourself. A villain doesn’t know where they’re going if they don’t know where they came from.
Think about why your protagonist is embarking on his or her mission in your story. They had a sequence of events in their lives that developed them into the person they are at the beginning of the story. So does the villain. What about your villain’s personality makes their own philosophy make sense to them?
How does your villain plan to go about achieving his or her goals? What tools or weapons are at their disposal? How much information do they have at the beginning of their quest and how much do they gain along the way?
People who achieve their goals took calculated steps to do so. Deciding how your villain takes steps toward their goals will progress the story and will keep them head-to-head with the protagonist. Often, the respective paths of the hero and villain run parallel. Think about the connection between your characters in the great web of the universe you are putting down on paper.
These questions could be answered with thorough character exercises. Decide how important this villain is to the story. The more important they are, the more you, the writer, should know about them. The villain may keep the reader on the edge of their seats, but you should be at least one step ahead of what your villain is about to do. Keep your friends closer and your enemies closer.