Question

i want some ideas to write a horror/scary story.

Answer 1

ghost or supernatural beings.
scary scenes.
describe the settings in a scary way with extra information.
describe the structure of ghost.
take your story in a very thrilling and interesting way so that readers are captured by your story.

Answer 2

describe the place you are for eg you are lost at the  temple far away from the city and nearby there is a haunted house. there are rumours about the house that there there lives a ghost and you are very much scared and you continue so on and make it in a scary and thrilling experience.