I have to believe that if you write all the time, you’ll get better at it. Unfortunately, I doubt if you’ll be able to tell. I don’t even know if anyone close to you could tell, either. It’s a kind of an incremental thing that happens very slowly and unnoticeably.
Depending on what you write, you may benefit from reading more stuff that is like what you write. I’ve found, over the years, that I can see more structural devices in a story than I was able to when I was younger. For whatever reason, foreshadowing is my favorite.
In any case, you might try to deconstruct some of your favorite stories, looking at the structure of the plot (the energy of the story at various times; movements in time; voice; points of view; etc). See if you can figure what, for you, makes it work. There is a formula to stories, I believe. I’m not sure I could tell you what it is, but I know it when I see it.
Disney, for example, tells some of the classic stories, over and over. Fish out of water. Buddy story. Coming of age. Cinderella. I find the story structures and themes to be most terribly obvious in Disney movies. I don’t know if this is something to be emulated (because it is tried and true and makes people feel comfortable), or to be eschewed (because it is so cliched).
My personal preference is to make things different. Or rather, since I don’t write, I hope the author will make things different. I like to be surprised. I like the story to go places I don’t expect, and to be about things that aren’t obvious. Of course, it needs to be a rollicking yarn, too. With characters who are likable, interesting and described with a keen eye and sharp tongue.
In the end, however, I think that writing is not something that can be improved just for a competition. It’s not like waterpik-ing your teeth furiously for the week before you see the hygienist so that your gums are healthy and pink. Writing is something you do for your life, not as a foot race. However you write now, that’s about how you’ll write next month. It’ll be years before you can know if you’re good enough to please yourself. Maybe you’ll never reach that peak, standing, as it does, in an atmosphere so rarified you need to bring your oxygen with you in a tank.