Ways to approach story structure are always something I am looking at, and not because I am looking for a formula, rather I am looking to bust apart any tendency towards the formulaic in my work. Understand your enemy.
Anything that has ever seemed phoned in to you is something that is done to a formula, where the individual applying the formula is not taking care to make sure that they are alive in the moment.
Grammar rules are the same to a degree – they are tools that you have to understand in order to manipulate them, but if they don’t serve the purpose you are trying to achieve, then pitch them out the window.
Beginning, middle and end, are a truth, but it does not mean that you can’t use them to lie. Hang that story over the edge of a cliff. Start at the end and roll back through time to the beginning. Jump around. Loop it. If it can work because you can see how it will work, but someone somewhere wrote a checklist for writing and it doesn’t comply, feel free to ignore that checklist.
A book isn’t a movie, and a book isn’t music, but there are acrobatics that a book can perform that these mediums can’t. Step inside a character and wear their skin and live their life, or in some interesting cases have the fiction hack your own reality. I watch and listen and read to enjoy, but I also learn.
There is something intuitive that unrolls from the thing that you are writing about – action shortens the sentences, and thought lengthens them. The way you write is pinned to a chassis of necessity, and pace and line length, and chapter length, shift as the focus of the story shifts.
If you are writing about movie you separate out the scenes into the slow down stroboscopic flow of the individual frames, you can burn that image in the gate, or you can let it flow fast like the mechanism that delivers the full speed vision to the eyes.
Write about music and add sing-song stresses to the syllables in the sentences.
Mirror a train in the punctuated rhythm of the text.
You have to develop an ear for speech, so that you don’t just have the person saying what you want them to say, but delivering it in the cadence and rhythms that you would expect that person to use.
Detective stories have conventions, so do fairy tales, and so do horror stories – learn all of them and you can bake a different cake. Believe everything is the same, and that there is one set of rules, and you are going to be in trouble.