I think it’s pretty easy to ensure there’s a story worth telling. Just start with:
1. Two characters.
2. With conflicting goals.
3. Who can’t just run away.
At some point, they’ll meet, then they’ll fight, then one will win (or both may win, in a genre like romance). Story over.
If there are interesting characters in an interesting situation, something interesting is going to come out of it.
I do have a bunch of half-written novels, but that’s just because I easily get distracted by the New Shiny and start writing something else even though I shouldn’t. I’ll get back to the others sooner or later.
Writing to an outline bores the heck out of me. In the last novel I published under this name, I had an idea of what the end would be when I wrote ‘Chapter One’, but didn’t even end up sticking to that. The novel before, I had a vague idea that the main character would be robbing a bank half-way through the book, but he went off and became a suicide bomber instead (just not a very good one).
That said, in some other genres I write under other names, it is nice to know that the genre has defined the basic structure and I’m just finding an interesting way to get from ‘Chapter One’ to ‘The End’ within that structure. It does eliminate some of the banging-the-head-on-the-table moments writing SF and horror.