For me, it's just tying everything together to make sure my story/stories actually flow well. One of the things I want to focus on is consistency and character development throughout my stories. How would my characters grow, develop, and change, and how does it relate to the plot and setting? Moreover, how would the readers feel? What kind of emotions would they feel relative to the characters in the story?
It's a lot of questions yes, but these are factors I want to consider if I want to write something really good and interesting.