Well, first, you need to define the beginning, middle, and end. For the beginning, introduce the characters and the problem. In the middle, have the characters face challenges and grow. At the end, resolve the problem. Also, consider subplots to add depth. It's all about organizing your thoughts clearly.
To make a good story outline, you could jot down the main plot points. Like, what's the inciting incident? What are the major conflicts? How will they be resolved? And don't forget to plan for character development throughout the story. That's a solid start!