There isn't a single answer to this question since everyone has different methods of brainstorming and coming up with ideas. However, there are a few general tips that may help you get started:
-Try to come up with a list of potential ideas before you start writing. This way, you have a bunch of ideas to choose from and you're not starting from scratch.
-Try to think of an interesting plot twist or ending that would make your story unique.
-Think about the type of story you want to write and try to come up with ideas that fit that genre.
-Think about your favorite books or movies and try to come up with an idea that is similar to them.