If you are stuck in your current work in progress, try to do a deep dive on your villain. Maybe this stays in the final draft, maybe it doesn’t make the cut, but either way it will help you to write something in the world of your book.

Try the following techniques:
Describe your main villain without talking about their eyes, hair, height, build, or clothes.
Describe them from the point of view of your protagonist.
When your main character thinks about this villain, what is the first thing that comes to mind?
What does your villain want most in the world?
What is their weakness? What could make them stop their villainy?