You can start by thinking about common fears, like being alone in the dark or encountering supernatural entities. Also, draw inspiration from real-life creepy places or events and give them a twist.
Look at real - life fears. For example, the fear of being alone in a dark place or the fear of the unknown. You can also get ideas from urban legends and folklore. Many of them have elements that can be turned into a great horror story. Another way is to think about what scares you personally and build a story around that.
You can get ideas by observing your daily life. Something as simple as a conversation with a stranger or a unique place you visit could spark inspiration.
Read a lot of different types of books and stories. Sometimes, a character or a plot point from another work can trigger your creativity. Also, think about your own experiences, dreams, or fears. They can be turned into great story ideas.
Use isolation as a key element. For example, a lone lighthouse keeper on a desolate island starts to notice strange lights in the ocean at night that seem to be getting closer each day. Another idea is to have a character lose their senses one by one. First, they lose their sight and then start to hear strange whispers. This can build a lot of tension. You can also write about a town where all the children start to disappear mysteriously, and the adults are too afraid to look for them.
Just let your imagination run wild. Think about things that interest you or things you've always wanted to explore and build ideas from there.
Read a lot of different things, like different genres of books and articles. That can inspire new ideas. Also, observe your surroundings and people's behaviors.
Read a lot of different things. That can spark new ideas. Also, observe your surroundings and the people in your life. Sometimes, just a random conversation or event can give you an idea.
Look around the room. Point out different objects and ask how they could be part of a story. For example, if there's a red ball, you could say 'What if this ball could talk? What would it say?'. Another way is to talk about their daily experiences, like going to the park or having a meal. Ask them what interesting things happened during those times. You can also use story starters. For instance, start with 'Once upon a time, there was a little boy who found a magic key...' and let them continue the story.
Read a lot of different types of literature. It can spark your creativity. Also, try imagining 'what if' scenarios and build a story around them for your flash fiction.
You could start by observing your surroundings. Maybe something you see or hear on a daily basis can spark an idea.