I use simple words and sentences when writing, since I just recently found my passion for writing, I decided to not just be a reader but an author as well, however, ever since I released my story I somehow found it... Lacking, I'm not a native English speaker and not used in deep English words, I also have hard times expressing the right expression of characters, so what do you think guys?
To be perfectly honest, words and sentences go a long way in making a story good, but it doesn't stop a story from being boring. You can have pretty sentences and a smooth and buttery flow in how they run into each other, but if the underlying parts of the story aren't there then it's going to be boring regardless.
I mean, look at the number of people who read machine translated stories. 9/10 times the grammar and mechanics of the writing are all sorts of messed up. But because the underlying parts of the story like the plot, characters, events... since they're ironed out, people will read on even through the mind-numbing pain and agony of MTL.
If you think your story is lacking something, rather than the words or sentences, it's probably a conceptual lack in the basis of the story.
Are your characters too flat? Too exaggerated? Unrealistic? Do they have their own goals, reasons, and beliefs? Or are they just pieces being moved around a board?
Are the interactions between your characters too stiff? Do they not sound real when they talk? Do you actually know the characters enough to where you aren't just puppeting them around?
What about your descriptions? Are you pointing out the right and important things in the scene, or are you just trying to cram in every last detail? Is there a detail you missed? Do you need all the details you put in?
What about your setting? Does it seem like a place where people or things would actually live? Are the rules actually self-consistent and not just wishy-washy? Or if they are wishy-washy, is it on purpose?
Hope that helps!