I'm 100% with jstro.

I can write dozens of emotional sentences, but each on its own won't make a story.

One of the things that helped me with my writing was learning to shorten a story which I have already written and turn it from 2000 words to 1500 and then to 1000 until I reached the 500 line. You'll be amazed to realize how many "weak" and unnecessary words we put into our stories!

Even writing a short story afresh and limiting it to 500 words or less is a good exercise.  Why don't we have a couple of those, with a prompt from the organizers??

Hanna