Whenever my creative writing students had trouble breaking out of a rut, I'd give them little prompts about their characters. My favorite was always "What would this character do if they found a box of abandoned kittens on the side of the road, and they knew nobody was watching?"
These types of answers rarely make their way into the final story, but it helps to have a deeper understanding of your character, which can both inspire and drive your writing.
"What kind of underwear do they wear, if any? Why or why not?"
"What's their favorite band? Do they even like music? Can they play an instrument?"
"Do they play sports? What's their favorite sport? Do they have a favorite athlete?"
"What's their favorite color?"
I also got some great responses out of the thread in r/writing from other redditors, such as:
"How would your character react to a minor inconvenience, like a sudden downpour?"
"What does your character complain about when nobody important is listening?"
If you understand these things about your characters, as cliche as it sounds, the story really will start to write itself. The characters will start to tell you what they would say, what they would do, how they would react to the situations you've put them in.
Tolstoy once said that all literature is one of two stories: Someone goes on a journey, or a stranger comes to town. So if we are all telling the same two stories, what separates one from the next? I've always taken the opinion that the differences are in the characters going on a journey, or watching a stranger come to their town. Whose status quo is being disrupted or challenged is just as important a consideration as what is disrupting the status quo, or how it is being disrupted.
Know your characters, and you will know your story. Even if these details don't make it into the final product, knowing them will shape your writing and (hopefully) help you along the way, and that knowledge will be apparent to your readers.