Join a writers group!
I wrote a lot of terrible fiction. I still do; I accept it as the price of trying different things. But for a long time, I had no way of knowing what was awful, or why it was so bad.
In fact, I was convinced that everything I wrote was amazing, and that anyone who thought differently just didn't get it. Many of those works were complex, but they failed for one simple reason: they didn't communicate with anyone. No matter how much I liked them, they weren't stories that interested other people.
You can write high-concept work designed for no audience but yourself, and there's absolutely nothing wrong with that. If you want to communicate, then you have to listen to and incorporate the opinions of real human beings. You have to figure out how to merge realities with readers in such a way that they feel compelled to follow along inside your head for a while.
Joining a writing group is a good first step.
The easiest way to find a nearby writing group is through meetup.com. I had the opportunity to join a genre-specific group (speculative fiction) but opted for one that included authors of several genres. While critique within the genre might be helpful, I thought it was a more valuable use of time to get feedback from a wide range of experiences. When a story appeals to the writers of crime fiction, fantasy, sci-fi dystopia, Tolkien fanfic, and gothic horror, I feel I'm doing something right.
In my weekly group, most of the writers focus on producing commercial fiction. They respect and reference literary fiction, but are equally bound by the conventions of salable genres. I won't lie; I was sort of a snob about that at first. It took leaving the group and returning to show me that these folks were giving me great feedback on my stuff. They had an understanding of plot and structure that I'd always ignored because I thought I was hot stuff and didn't need to bother with silly conventions. And they were avid, articulate readers. Their opinions were a microcosm of how a wider pool of readers might react, with better tools to dissect the text and describe their suggestions.
If you eschew direct communication between fleshbags, you may prefer an online critique group. Two of the most popular are:
- Online Writing Workshops - There are sub-groups that focus on literary fiction, romance, and science fiction/fantasy/horror. There's a free introductory period, after which you pay a yearly fee. I find the science fiction forum isn't quite as active as it was in the past, but I received some good feedback there in the past.
- Critters - This workshop focuses on sci-fi/fantasy horror fiction. For other genres, check out critique.org. This group is free to join, but demands a serious commitment from its members - an average of at least one review per week. It comes highly recommended.