You could start at the very beginning, like introducing the main characters and the setting. For example, if it's a story about a journey, start with the character's decision to embark on that journey and describe where they are from.
Characters, for sure. You need to create interesting people that the readers can care about. Also, a plot, which is what happens in the story. And a setting, like a spooky old house or a sunny beach.
Use vivid descriptions. For example, instead of saying 'the tree was big', say 'the ancient oak tree towered over the small clearing, its gnarled branches reaching out like twisted arms'.
It's not set in stone. You might consider beginning when there's a significant change or event that kicks off the story's momentum. Or you could start with a mystery to hook the reader's interest.
I think you can start at the moment that sparked the entire story or at a point that raises a lot of questions and makes the readers curious to know more.
Well, you could begin by thinking about a character you want to focus on and what kind of situation they find themselves in. Build the story around that. Also, having a clear beginning, middle, and end in mind can help structure your tale.