What's most important to me in a story (comic or otherwise) is probably the characters. If the characters aren't likable, relatable, inspiring, interesting, or at least just fun to read about, why would anyone care about what they go through?
I also really like creative world settings. Modern day and standard fantasy are fine, but what really draws me in is a world that is entirely its own; a setting that is creative and original. Things like alternate history, fantasy, and sci-fi worlds that are memorable, inventive, and interesting.
That's why in my comic, I try to present a unique fantasy world, and characters I would want to read about.