I would advocate asking someone you trust to view the story and give you feedback, rather than posting it to the site. If you have certain questions, problems, you're stuck, etc., it can be helpful to ask for specific feedback with a page or so, but I would encourage you to use the messaging system rather than the public forums for more in-depth feedback.
Publishing stories which are unfinished tend to get a response, albeit not always a positive one, but also make it so that when your story finally IS published, it is not a fresh, new story to be devoured by the public.