Hi Maddie,
Character development can make an okay story much better. The action can start right away, and the characters can be developed along with the story. Some of the best stories I've read, don't really get into the history of the characters until later chapters, they let the actions of the characters speak for themselves.
Now, if you're talking about writing something for Penthouse or other magazines, in their letters section, there is a set format to follow. :-)
Since I'm picky, I also care about:
* pacing,
* spelling,
* grammar,
* point of view/perspective,
* story layout
* consistency of actions
* and a good plot if one is required.
For example, if a story starts in an "first perspective" point of view, then pops into third person in the fourth paragraph, I'll probably stop reading.
Consistency isn't only about the actions or the characters, it can also be about spelling. Did the author start with an American English spell check then switch to UK English? There's a pet peeve for me.
Because writing and editing is so very important to my day job, when I read a story I want to get lost in it. I want the story to take me away from everything and just be something I can enjoy.