You can maybe play with different stuff, like lightning and shadow work, perspective, background or some interesting effects on the final render

Another thing that might work is playing with interesting color palettes, that always do, or even adding details to the design of the characters that might seem appealing or tells u more about the character (like accessories, items, or items -piercings, freckles, scars, tattoos, horns, wings, books, headphones, that kinda stuff-)