I'm currently reading Cronin's Mary and O'Neil, which is his first published collection of stories. The stories are interconnected and revolve around these two characters and their relationship--and that of their family and friends.
One thing that has been going through my mind now that I've been exposed to Cronin's 'know what your characters don't want to tell' mentality is that exact question: What secrets are these characters keeping? It's not all that hard, because Cronin doesn't hide their secrets from the reader. What I've noticed is the way that these secrets/hiding places are revealed.
He takes his time.
I've noticed in my own short stories that I think the word 'short' and that ultimately leads to 'rushed'. Just because a piece has a smaller word count does not mean that I should sacrifice character development, good dialogue, or scene setting.
In the first story in this collection, Cronin introduces O'Neil's parents, who are going to visit O'Neil at college soon. Cronin spends a good deal of time in the kitchen with the couple, establishing their relationship. Pertinent details are revealed. Then, we switch to just O'Neil's dad. Something else is revealed while he spends time in his office and then a restaurant. And so on until the conclusion of events.
Sound slow? Sound boring? Maybe. Noothing moves too quickly, a lot of information is given out, and it's still short. By the end you understand the characters, their motivation, and the why of things. It's satisfying. I think this pacing element ties to the keeping secrets element Cronin discusses.
I recently read a brilliant short story by a friend of mine. There was a fascinating situation involving a boating accident that results in a death. As I was reading it, I fell into the story. When I got to the end, though, I was strangely unsatisfied and I think I figured out why from Cronin.
When I was doing the critique I called the main character's 'arch' into question. She just didn't seem to grow or change or any of the other words that we writers use to describe a character we just don't understand motivationally. But I realized, after reading Cronin, that what I was missing was the main character's secret. What was it she wasn't telling anyone? I need to know why she was acting the way she was--and while there were hints, nothing was stated outright. I think with just the addition of that piece, my friend's short story would work beautifully. (Because it was super close to begin with.)
Between Cronin and the epiphany over my co-writer's story, I'm going back to look over the short stories that I haven't sold yet to see if maybe that's why. Perhaps the reason my short stories aren't working quite right is two-fold: I need to find out what the characters aren't telling anyone, and I need to take the time to reveal that secret once I know it. Gotta remember there's no rush--tell the story how it needs to be told.