Tossing in my Two Cents here as well:
When it comes to World, Characters, and let's call it Plot, because all three of these create the "Story", the easy answer is IT DEPENDS. Of course--that explains absolutely nothing.
(Plot = This happens and this is why, while Story = And then this happens)
When I dedicate myself to a story, I decide first what the most important thing is, and then I flesh it out just enough to be able to see it in my head without any of my notes.
Sometimes, based on inspiration, it's two characters that interact; sometimes it's the concept of a world based on a "What If?" and sometimes It's "omg, I just really want to rewrite romeo and juliet's plot."
Be that as it may, I can only give an example of my process:
1/ Inspiration based on tons of sources, half of which i'm not aware of or finding a notebook where I wrote 100 prompts for myself ages ago. Pick one of those inspiration and have a gist of Main character(s) [Max. 2 at this stage], setting and plot's key conflict.
2/ I like Character-cause and driven plotlines, so I focus on the one or two key characters that the story is about; Ideally, I focus on telling the story from one character's POV so it's easy to have a protagonist or two if the romance or partnership is important to me.
3/ One sentence plotline that summarizes what the entire story is about. Expand into 3 acts, one sentence each; Expand each sentence into it's beginning middle and end; Continue expansion until the very act of writing the story has given me necessary characters (Allies and Antagonists mostly because I start with my hero or heroes)
4/ In Step 3, on the side as characters and situations arise, I world-build and flesh out characters that will, in turn, affect the story.
5/ Finish the expansion and split the story into given acts and chapters/scenes; and proceed to create all concept references needed to create the comic itself. The rest is just pounding out pages.
At one point, though you may start with one order in mind, everything tends to happen in tandem.
For a short story, I find Characters most important
For Long-form Stories, A solid world is most important at first, then Characters.
This is just how I do things though xD.