I attended the panel on short stories at the con. The speakers were many of the folks listed below, as well as other renowned short form authors.
Best advice, in two parts:
1. Ask the story question on the first page.
2. Answer the story question on the last page.
The story question = what's your story about, man? Like right now I'm writing a story that centers around the concept of The Oath of Brutus. It's basically let no man be king of Rome. So this government assassin eliminates people who would be king. And that's all I can say, cuz I gots my own twist on the whole jig, of course. But on the first page, he is given his assignment, and on the last page he will conclude the assignment. Or not. :>