The Electric Spec editors have posted before about the importance of the first page--even the first paragraph--of a story. The reality is that we have lots of submissions to go through and if we're not impressed with the beginning, we may never get to the end. I wish I had the formula for the perfect story opening, but I don't. However, here are three things I've seen in the first paragraph that have made me want to look at the next story in the pile:
1) Passive voice--especially multiple sentences in a row of passive voice.
2) Lack of a clear protagonist. This usually means there's a long narrative that reads more like a newspaper article than a story. Also, this can be when multiple characters are introduced but I don't know which one the story is about.
3) Generalized descriptions. For example, "The short-haired man stood in the room. Across from him, the woman sitting in the chair smiled." I don't get a picture in my head from these sentences. I don't even know where or when the story takes place. Give me some details. Maybe something like this: "As usual, Alfred, the raisin-faced weirdo from accounting, hovered next to the coffeemaker in the break room. Jane slouched in the hard plastic chair across from him and couldn't help but smile. Tonight, Alfred would die a slow, painful death."