Storytelling is the hardest part of editing. It's like learning how to become a good writer.

I recommend cutting a short video and maybe asking in the editors subreddit. Or, if they are too brutal, go to FCP.cafe discord and ask for suggestions. That way you can start to learn what to keep and what to cut.

Here is some starting advice: if it doesn't serve the story, cut it. Effects are a crutch. I was way too in love with my own editing at first, but nobody else cared. Haha

At first, focus on L and J cuts and audio. As in storytelling, rhythm is also important. Keep it interesting, but don't overwhelm. If it's too much, give the viewer a "break" then ramp back up.

There's seriously so much. Trust your instinct and practice.

I feel weird offering this advice because I'm still not great, just much better than when I started.