Granted the topic has the whiff of stale theory, but it is surely of great importance. Even if I am not going to solve it right now-- to say the least-- I still want to add some further reflections.
Examine the question in a different context, one that we owe to Harold Bloom's book: "The Anxiety of Influence."
According to Bloom, poets, and by extension other artists, learn their craft by studying the work of their predecessors. If you are going to write an epic poem you will learn about it by reading Homer and Virgil and Milton.
If you are new to the game, the chances are very good that you will adopt the stylistic mannerisms of your predecessors. Spend some time reading Henry James and your novelistic endeavors will sound like Henry James.
If a reader picks up your novel or poem and is immediately reminded of some other writer, then you have not found your own voice.
The poem is not yours if it reads like ersatz Wallace Stevens.
Of course, there is nothing wrong with these first efforts at imitation. They belong to the learning process. You cannot escape it by trying to create your own literary genre.
Having your own voice, having your own signature, putting your stamp or your mark on your work... all of these work because they give your reader the sense that you have remained within the genre.
If you try to invent your own genre your readers will simply not understand what you are doing. It's a little like trying to create your own language. A new language would help you to overcome the risk of saying something that would remind your listener of someone else. Unfortunately, no one would be able to understand a word you were saying.
How then do you overcome the tendency to imitate? How do you find your own voice?
Harold Bloom suggested that the process involve a series of psychological ordeals. This may feel like a psychotherapeutic process; it may feel like a mystical journey; it may even feel like a young troubadour undergoing a series of ordeals to prove that his love is true.
I to see it in terms of hard work, of extensive revisions, or reworking the material until it gains its own integrity. Poets whose work feels excessively derivative are either young or lazy.
Be that as it may, Bloom proposed that poets wrote poetry about their struggle to overcome the influence of their predecessors.
Certainly, Romantic poets, an area of Bloom's expertise, were especially concerned with the struggle with their literary forebears. One reason might be that many of them were very young, and this form of anxiety seems endemic to youth.
Nevertheless, saying that poetry is about the poet's struggle to find his voice, to establish his signature, feels solipsistic.
It confuses the act of making something your own with the act of making it all about yourself. If it's all about you, you do not really need a signature.
But if it's all about you, why would you imagine that anyone else cares about it. And if you believe, as Bloom seems to, that the struggle of the epic poet with Homer mirrors the Oedipal struggle that Freudians believe we all engage in, then I would reply that the Oedipal struggle has nothing to do with finding your own voice. It's about copulating with your own mother.
Poems must touch an audience. They must address the concerns of their readers, which are not necessarily the concerns of the poet.
A poet must find his voice, and he may certainly write about the process of finding it. If he does, he will be writing about an object, in much the same way that a self-portraitist draws the image he sees in the mirror or a painter paints his model.
What ultimately matters in art is not what it says about the artist, but what it says about the object, the model that inspires the work.
Isn't art about how the artist recreates his model, making it his own? Not so much in the sense of possessing the model, but in creating a new version that speaks to the concerns of other people.
If your poem has nothing to say no one is really going to care whose it is.