The more I write, the more I internalize the fact that it all comes back to character. As I've mentioned before, the author Chuck Wendig really hammered this into my brainspace. Right now I'm revising my novelette The Man in the Red Paisley Suit, and coming back to this lesson is really helping.
Characters are the reason we have a story in the first place. And yet it's amazing how easy it is to forget that they need to push the story forward by their actions and needs. Characters are people, people! They have backstories and desires and positive traits and negative traits. And that goes for "good guys" and "bad guys". Human beings are so incredibly complex. So are the best story characters.
If you don't know what happens next in your story: ask your characters.
If you don't even know where to begin your story: ask your characters.
And if you don't know how your story ends: ask your characters.
Your characters will always have the answers. It's up to you to ask.