NOT getting published is really easy. In fact, many writers are very good at NOT getting published. The reason? They are often a little bit rubbish!
My experience is that good writing, presented correctly will ultimately find a home. A well written, well edited story, with a good cover letter and synopsis, offered to the correct people will most of the time end up in print.
So why are you NOT getting published?
Is your story too weak?
Does the manuscript need to be tighter?
Could you edit it just one more time?
Is the spelling incorrect?
Is the grammar a bit off?
Does your cover letter stink?
Is your synopsis just not good enough?
Are you sending it to the wrong people?
Have you just given up?