In the book "Writing Fiction For Dummies" it describes that to get a good them is to firstly develop a plot and look for a recurring theme and work with it from there.. I am new to the writing scene so I may be wrong on this, in which case a more reputable member may be along shortly.
It can happen either way around. There are plenty of examples where a writer has set out to write about theme X and developed a story that lets them explore it, and on the other hand there are many novels (probably more, not that that counts for anything) where the author begins with a story or idea for a story and from that a theme becomes apparent as described above. Personally, I prefer writing and reading stories that use that first method, although if the book is good you can rarely tell which is which.
If you plot out your stories before you write them, then the theme will probably make itself known pretty quickly. If you write by the seat of your pants, a theme is useful to steer the story back on track once it inevitably kicks off the rails and goes headlong into a tangent.
I personally think that it's important to have enough of a "plot" to sustain a story through the first quarter or so, but after that I heartily recommend just letting the story go where it wants to. I think one of the worst things you can do is reach a certain point in your writing of it, come up with a really great idea, and then dismiss that idea because it takes you off in a different direction from any strict plotline that you've dreamed up. If you're determined to stick to a particular ending, then it should still be possible to bring the story back to your plotline, a bit like coming off the interstate and taking the scenic route, but still arriving in the same city at the end of your journey! Always try the road less travelled.
why worry about 'theme' at all?... if you're telling a good story with a workable plot, why would it matter if there's a theme, or what it might be?
Good point. There's really no rule that states a story has to have a theme. In fact, your readers will probably find one--probably not even the same one!--even if you don't consciously try to weave a theme in there. Just focus on writing a good story; let the world muse about what it means.
Themes often work their way into a story without conscious intent on tje part of teh writer, frequently reflecting the wriiter's personal beliefs or ethics.
