Often it’s the diction that matters as much as the content.
When you return a cart to the cart corral at my grocery store, there are two sides, designated for different sized carts. They are kindly labeled: Large and Small.
But whenever I get there, in my head they’re labeled Big and Little. Why? Is one pair of words better than the other? No, I don’t think little is innately better than small or that large is worse than big. Those words are just my particular word preferences. Having specific feelings about word choice is what makes my diction mine.
The same is true for composing and arranging. What makes you sound like you as a writer aren’t the broad choices of repertoire, instrumentation, or genre. It’s in the ways you shape a melody. It’s in the particular ways you notate a rhythm or voice a triad. It’s in 1,000 tiny choices you make based on your personal preference.
The trick is to expose yourself to enough music – and write enough yourself – to develop those personal choices. I didn’t start preferring little to small right away; it developed over time. Then start making those choices every chance you get.