In my survey of writers' biggest challenges, this one came up:
"My greatest problem is deciding on the structure for my project, because there are so many different approaches that can be adopted. I don't want to waste time going down what may turn out to be a blind alley."
I hate to be the bearer of bad news, but blind alleys are inevitable if you want to be a writer. I doubt that any writer, including the greats like Dickens and Twain and Austen, didn't venture down quite a few in their time. In fact if you read their autobiographies or biographies you'll find most of them had projects they abandoned because they realized they'd gone in the wrong direction or written themselves into a corner. Sometimes they figured out later--at times, years later--how to salvage or fix those stories, other times those tales remained unfinished.
This desire to have a guaranteed structure leads many writers--especially scriptwriters--to search for a formula or template that fits all stories. There isn't one. Yes, the hero's journey fits a lot of stories, but by no means all of them.
WHAT DO YOU WANT THE READERS TO FEEL?
So how do you find the right structure for your story? By delving deeply into the story yourself, figuring out which part of it you want to tell, and letting the characters lead you. That's not the same as not planning the story. I do suggest having at least a rough idea of where you're going before you start writing.
One important question is what's the emotional story you want to tell? What do you want your readers to feel?
Let's look at one story that you might choose to tell: a woman kidnapped when she was a teen-ager and held a prisoner by a man until, after ten years, she escaped.
Do you want the reader to feel what it's like to be wrenched from a happy life to one of terror and uncertainty?
Do you want them to feel what it's like to forget who you were and become the person your captor wants you to be?
Do you want them to feel what it's like to be a prisoner even though you've done nothing wrong?
Each of these would call for a different structure although they'd have elements in common.
For the first one you'd want to include quite a bit about the life of the girl before she was taken.
For the second one you'd focus on the time when she gives up fighting and comes to believe that she has to accept the new life forced on her.
For the last one you might focus on the minute details of her imprisonment.
There are still many ways each of these could be handled but each one has clues as to the structure it wants. That may sound like a funny way of putting it, but I do think that you have to make the story the boss and the structure the servant.
And when you find yourself having to choose between several ways to go, you won't go wrong if you revisit that question: what do you want your reader to feel?
There will still be times when you go down blind alleys, but this strategy may help you do so less often.
(Classic authors like Dickens, Twain and Austen, as well as modern writers like Vonnegut and Amis had advice for writers. I've compiled it and added guidance on how to apply it, in my book, Your Creative Writing Masterclass. It's published by Nicholas Brealey and available from Amazon or your other favorite bookseller.)