I tend to think of my e-books on Amazon as very small needles in a very large haystack. My biggest challenge has been trying to do things other than writing to make it more likely people will find my needles. It has not been easy, and I've lost enthusiasm for that part of the writing process more than once. Every now and then, someone stumbles across one of mine and decides that it shines more brightly than all those other needles.
My guess is that it's not any easier to find a print or on-line magazine where your story fits well enough to trump all the others that came across an editor's desk that day. I've been gathering a few here and there for flash fiction. Haven't submitted any yet, but you folks might take a look at Everyday Fiction (1,000 words), Flash Fiction (500-1,000 words), Page & Spine (1,000 words), Splickety (300-700 words), and Toasted Cheese (500 words).
Cheers!