Applying the rule of the core word is really helping me make my writing stronger. The idea is that every sentence has one core word that turns it. In other words, every sentence is about something, and that something is signified with one word. The strongest sentence is the one where the core word is at the very end. This is the sentence that keeps us reading, holding us in suspense, until we find out what the sentence is really about. It can also be in the middle, but then the punch is much weaker. And if it's at the beginning, there is no punch to the sentence at all, but then it is also most poetic. So you're swinging from suspenseful to poetic in all your prose (which is your choice and which then determines what kind of book you're writing). And so here I was, writing an opening to a scene that signifies a potential of two characters having sex. And I'm not even introducing the characters yet.
This is how I would've written it in the past (and I did, before I corrected myself; core words in bold):
There was only one bunk in the conductor’s compartment. It was made up with fresh sheets, two pillows, and a blanket.
And this is how I wrote it just now, making sure the core words for both sentences are at the end:
The conductor’s compartment had only one bunk. It was made up with fresh sheets, a blanket, and two pillows.
Just this one little thing, and the difference is huge. I'm amazed at this, really. Now whenever I read any book, I notice this, and I can see how the story could be stronger if only the author moved some words around. This is powerful stuff. I can also now see how some authors know exactly what they're doing, know their craft, and so they punch me in the face with every sentence, and I'm helpless, I keep reading because I can't stop.
Take a look at your writing and try dissecting a few sentences to see where the core words are and how you can restructure your sentences to make them have more suspense, carry more meaning, by simply putting the core word at the end. Fascinating, isn't it? I only wish I didn't need to sleep or eat or do any of that annoying stuff, and just learn. Because learning this little idea had made a huge impact on the quality of my writing.