I’ve written short stories, but have not finished the one I’ve been craving to explore. Time and again some ‘thing’ always stops me from getting very far. Usually, it’s been my indecisiveness. I often ask myself:
“What if I make this character more troubled than I was originally thinking?”
“What if this new species I invented suddenly has this unique trait?”
Or I write a scene and can’t decide if it’s any good so I stop working on it. I’ve only taken two writing courses, by my first writing course taught me some important tricks. If you feel passionate about an idea, whether it’s for a few hours or days, it is worth documenting. That’s not the trick though!
The Trick is in the Editing
When you look back on that one poem about that rabbit you saw you may or may not fall in love with it all over again, but you’ll have a better sense of what part is a good idea and what does not work.
When you come back to a work after some time has lapsed it is a lot like getting a second opinion. You’re not in the same space you were in a month ago, and you’re new look might uncover something worthwhile. Edit the piece until you are satisfied then take a break from it for a couple of days and edit it again. Or take it apart and use some of it in another work.
The bottom line is you must go back to your previous writing and give yourself the opportunity to make something great! Things don’t come out that way. This way you won’t be giving up on yourself. 
All About Stories 