Cli·ché (klee-shay) also cliche (kl-sh)  n.

1.) A trite or overused expression or idea: ?Even while the phrase was degenerating to cliché in ordinary public use... scholars were giving it increasing attention? (Anthony Brandt).

2.) A person or character whose behavior is predictable or superficial: ?There is a young explorer... who turns out not to be quite the cliche expected? (John Crowley).
(source: http://www.dictionary.com/ )

It's not something pleasant to hear, or pleasant to say.
  But what's to be done, when you find it one day
   in a pile of mismatched lines like a stack of hay?
  They aren't hard to spot, like white backgrounds
   and black dots. You'll know what I mean, in
  a minute or two, but cliché phrases and ideas
will be the death of you.

What does a word or phrase need to do in order to become cliché?
There is no patented test that words must go through nor a physical examination of how healthy they are in writing. The cliché, in most accepting patterns of thought, comes from experience. A person that has extensive knowledge of Anne Rice will obviously note that Vampires are cliché in writing, provided said person does not stray from that genre too often. This is true in most other genres - too many robots in Science-fiction, too many murderers/rapists in horror fiction, and such like that. We come to the conclusion that cliché, in essence, means that a term or phrase is overused in a certain aspect. In our case, however, the aspect is poetry.


What determines originality/overuse?
With all the perpetual copycatism in television, music, and movies, where does the originality lie? Not to say that literature is devoid of overused ideas and storylines, but there's something about writing that allows one to be more creative and adventurous. With all the millions of words and languages to write in, the same story can be built upon and made better by being given greater character descriptions, greater imagery, greater depictions of events, and so-forth. But is the story still, in essence, the same? Yes. There will always be a relative sense of 'connection' to one person or another. Whether someone relates the poem to the "Ghostbusters" movie, Shakespeare's "Macbeth," or a song on the radio, a single person's announcement that your (or any) writing is cliché should not affect you greatly. When an entire workshop group, however, informs you that they've all "read this piece before" in one way or another - you should take into consideration that you need to experiment with your writing. Perhaps even scrapping the piece you are working on entirely and starting over. This will challenge you to no end, but overcoming cliché in writing is going to be a constant endurance test. The practice and experience you gain early on will make things much easier down the road.


Alternatives to avoid cliché.
Experimenting comes in many forms, it can be as simple as changing your usual topic to being as complicated and shifting structure forms. The best way to experiment is: well, there isn't any. Everyone has their own niche that they will eventually find while experimenting. With the right amount of devotion put into it, of course. A writer can only be as successful as their pride will allow them. Being modest will not help you in writing, but at the same time, being overly confident will only upset the writer when their work is not responded to with consistent praise. There exists a balance in interpreting comments, as well. If another writer tells you that "[this] line needs revision because it "doesn't sound good"," take his/her word for it. If a non-writer tells you the same comment, take their word for it too. All perspectives (good AND bad) will help you determine what your audience finds most important in your poetry.

If all else fails, and you feel that you can't escape the "cliché effect," take up screenwriting.
At least you will have a career that will pay you for re-writing old scripts.