Often as I read slush, I wish our aspiring authors had critique partners (or better critique partners). I wish I could tell the author: 'your story doesn't start until page 3' or 'your beginning and your ending must relate to each other.' Story beginnings are crucial. If I'm not hooked on page one, I usually won't make it to the end of the story. Show me what your story is about on page one.
I suggest authors think more about their story before they begin. What, exactly, is this story about? Who is it about? What's the problem? What's the resolution? What's different at the end of the story? What emotions do you want to evoke in the reader? You don't have to write these answers down, but you should know them.