The key element is to establish a strong voice. You need to make the narrator's personality clear right from the start. For example, if it's a cynical character, use a sarcastic tone. Another important thing is to introduce the setting quickly but vividly. It could be as simple as 'I woke up in my small, stuffy room, the peeling wallpaper a reminder of how long it had been since this place had seen any care.' Also, hint at the main conflict early on. Maybe the narrator mentions a strange letter they received that morning which will drive the plot forward.
One important element is creating an engaging hook. This could be an interesting thought, like 'I've always known that my life was different, but I never expected it to take such a strange turn.' Then, it's crucial to develop the character of the narrator. Share their quirks, fears, and desires. For instance, if the narrator is afraid of heights, you can mention how they feel looking out of a tall building. And don't forget to set the time period clearly, whether it's modern day or a historical era. This helps the reader better understand the context of the story.