Addressing some concerns:
Does ‘finding your theme(s)’ involve sitting in a corner catching up on all the newspapers and current events and working out what you think of everything?
Does it mean sleepless nights as you try to figure out the Meaning of Life (or at least, your Life)?
Does it mean radically re-writing everything you’ve penned so far because you missed the boat somehow?
It’s a ‘No’ in answer to all of the above.
In fact, let’s start with the last concern first. If you’re worried that, as a fiction writer, you have not paid any attention to this mysterious thing called ‘Theme’ and have therefore wasted your time so far, you can rest assured that this won’t be the case. How can I be so sure? The answer is in the statement above: you’re a fiction writer.
The mere fact that you have been writing fiction means that you have to some extent been dealing with Theme.
I had a friend years ago who never read fiction. He studiously avoided stories, and would always prefer to pick up a non-fiction tome if required to read anything. ‘What is the point of reading all about things which someone has just made up in their heads? Give me facts any day,’ said this modern Gradgrind. His residence was full of text books — not a novel to be found anywhere. He was a curious cove, in this sense that he found it a little difficult to fit in with his contemporaries. That’s largely because, as human beings, by far the bulk of them were living an existence day by day which overlapped with the world of fiction.
Most people are not like my friend: most cannot get enough of fiction, whether it comes through novels, short stories, television programmes, theatre or in some other way. And then are just the obvious ways in which most people’s lives are intertwined with the worlds created by stories: less obvious, but even more prevalent, is the way in which we interact with each other using figurative language. We depart from the literal all the time — the way we greet each other, the way we hold conversations, the way we text and email, our language is soaked in figurative and metaphorical expression. So much so, in fact, that I need only to refer to my own last sentence to give you an example: ‘our language is soaked’. Have I taken pages of printed words and bathed them in some kind of abstract quality? No, I have simply used a common English figure of speech. The language is loaded with these.
Truthfully, the only form of language not utterly riddled with this kind of metaphorical way of communicating is that of science. Scientific papers of all kinds strive to meticulously remove the figurative and un-literal. This reflects the whole movement of what we call ‘science’ away from an subjective/objective blend - a unity of vision with which we are all familiar on a daily basis - towards some kind of coldly rational and purely objective way of describing ‘reality’. The resulting understanding of 'reality' has empowered people to do wonderful things with material nature, but it is one in which it could be argued that the baby has been thrown out with the bathwater. Or at least, it could be argued that way if metaphors like that were permitted.
So, getting back to the point: if you have been attempting to write this thing called ‘fiction’, as opposed to the driest of dry scientific analyses, then chances are that the mysterious ‘quality of form’ which we call ‘Theme’ has crept in there somehow.
Perhaps you have penned a horror story about a woman trapped in an asylum? You thought you were keeping things pretty ‘objective’ and ‘cold’ to try to capture the chilling reality of her predicament. But even with your best efforts to cut out anything non-literal, you’re still dealing with invented items called ‘characters’ in invented places called ‘settings’. Even if you had set out as a journalist to tell the tale of a real person trapped in a real asylum, staying as closely as possible to the mode of reportage rather than invention, as a writer you were still making selections of what to include and what not to include in order to achieve an effect upon a reader: a subjective, emotional effect, not simply a rational transference of information.
Machines transfer information and have no intention; writers transfer shaped material with the intention of creating an emotional effect upon a reader.
So chances are that ‘Theme’, however unrecognised or undeveloped, already exists in your material. In the case of the example given above, the story of the woman trapped in an asylum, what, then, could be the ‘Theme’?
You have to look at the piece as a whole. Breaking things down into component parts can be useful, but moves us along a scientific path rather than a trail of ‘fictive understanding’. Take a look at the ending of the story: does the woman escape? Or is she left doomed to spend her time locked in a cell, insane? Structurally, is the tale full of mini-cliffhangers which never get fully resolved or explained? Or does everything make sense as some kind of hoax or elaborate conspiracy when we close the book?
Broadly speaking, a piece of fiction usually has built into it an upswing or a downswing. Either the readers track along with the characters through a set of episodes leading to some kind of insight, resolution or ordered finale, or we track with them down into intended obfuscation, open-ended questions and darkness. What your ‘Theme’ is composed of can at least partly be answered by what type of ‘swing’ does your fiction normally possess.
Either type is fine: King Lear, one of the downiest downswings in literature, is unquestionably one of the greatest pieces in the canon; Frank Capra’s Christmas film, It’s a Wonderful Life (the clue is in the title) is the opposite thematically, but remains one of the mightiest films of the Twentieth Century. You might specialise, therefore, in horror and deep irony; or you might be a playwright of romantic comedy — your intentions are not questionable here, only your understanding of what you are doing and your skills in making your work as good as it can get.
The big difference, and the big thing to work on, is making sure that Theme stands out enough for editors and readers to notice. Your work has to be turned from flat, two-dimensional and solely linear storytelling to more rounded, three dimensional and multi-layered fiction — or at least it does if you want it to be seen and sought after.