I'm writing up a new story (which I've asked for help on in a few other places) which is a little outside my forte. The majority of my current work is saturday-morning cartoon stuff, light fantasy or allegorical. Now I'm writing a science-fantasy drama that is darker than most of my work. It features heartbroken antiheroes, well-intentioned extremists and keep-to-yourself people who get caught in the crossfire.
Now, if there's something I've seen a lot of, it's stories with grit that falls flat in one of 2 ways:
1) The premise or events are so absurd, stupid or far-fetched that you either laugh at its absurdity or boo at its stupidity. You just don't feel the grit because you can't take the setting, the characters or the plot seriously enough to care.
2) The story turns into "When hell goes to hell" and everything sucks beyond all possible hope. Here, readers are inclined to laugh at the over-the-top Eeyore-grade pessimism of it all or, more often, simply give up on the story all together under the pretense that there's no point in anything.
I'd like some tips for myself and other grit-yearning writers on how to find the happy medium between too little and too much. How can I adjust my voice to keep readers turning pages and enjoying the story while feeling the tension and understanding the pain of my characters?
I've been looking for advice on this for months now, but haven't been able to find anything helpful. I apologize if this is a duplicate, as I'm sure this question has been asked before, but I simply haven't been able to find it.