One way is to draw from your own experiences. Think about a unique event in your life, like a strange encounter during a trip. For example, I once met a man on a train who was traveling with a cage full of exotic birds. That could be the start of a story about mystery and adventure. Another way is to combine different concepts. Take a fairy - tale setting, like a magical forest, and mix it with a modern - day problem, such as pollution. This can create a really interesting and original story idea.
Look at the world around you. Observe people's behavior, their relationships, and their emotions. You might see a couple having an argument in a park. What could be the reason behind it? Maybe it's not just a normal lovers' quarrel but something related to a hidden secret or a past event. Build a story around this observation. Also, you can get inspiration from dreams. Sometimes our dreams are full of strange and wonderful scenarios that can be turned into great story ideas.