A Theme is a big idea (kind of like a moral) in a piece of writing; it’s what you say when someone asks you what a book is about. A Motif is some “thing” (an image, a color, even a location, etc.) that recurs throughout a piece of writing and takes on symbolic significance because it relates to some big idea in the story. So the Themes (there can be more than one) and Motifs in stories are linked. (Don’t confuse a Motif with a MacGuffin, which is a plot device that acts as the impetus for a story but is actually fairly interchangeable. A MacGuffin is the thing that characters are looking for, usually in detective stories, but that thing could actually be just about anything, i.e. usually some kind of treasure. In the film The Maltese Falcon, the falcon is a MacGuffin. The important thing is the search for the falcon; it could actually be just about anything. A Motif is essential to the plot, on the other hand, and not interchangeable. MacGuffins come in many forms. In scifi, they’re often called “Big Dumb Objects,” for example, because the plot often revolves around some mysterious object.)
I tend to have pretty heavy themes in my writing, and early on, I frequently browbeat my readers with these ideas. Some advice I was given long ago is that themes shouldn’t be pushed; don’t go into a story thinking, “I’m going to write about _________(insert theme).” Go into a story trying to write a good story; the theme will find its own way in (because it’s on your mind). I’m a big believer that stories should reverberate beyond their own dimensions; they should have a “point,” if you will, beyond just being a story. Stories, I think, help us figure out how we should live, who we should be, and they give us insight into other lives, other ways of thinking. They are philosophical as well as entertaining. This is dangerous territory because heavy themes can easily cross over into propaganda, which can be enjoyable but usually isn’t. Some writers will be provocative for the sake of getting attention, but in today’s oversaturated culture, one has to go very far to get even a passing moment’s attention, and probably sacrifice everything meaningful about a piece of writing. (Which isn’t to say don’t be provocative, just have a point with it.) As loathe as I am to admit it, I think my old writing professor was right; themes will force their way in.
Motifs, on the other hand, are a sign of thoughtful construction; they are the ornate embellishments that help the story rise to beauty. The idea that a writer has layered elements like this into the story shows that some thought has gone into it and some skill. Symbolism, in general, helps demonstrate craftsmanship and elevates writing to the level of art. You’ll notice that every “literary” story and novel out there contains symbolic elements. Even Hemmingway, known for his spare writing, loads his short stories, especially, with symbolism. This reaches back to the beginnings of storytelling, when symbols were used to represent difficult ideas or social norms in a more easily-digestible way. (If you can’t learn the words, at least learn the tune.) But really, motifs, and symbolism in general, are just tools; they’re other ways of telling stories.
It’s kind of silly to try to dictate things like this, but regardless, I find it useful to strive for including at least one moment during a story, maybe at the end, maybe at some key moment, in which the language rises beyond the page and reaches into something profound. This is usually accomplished by symbolism, though very strong, evocative description can accomplish the job too. That powerful, resonant moment is what really sticks with a reader after the story is finished. When we think of The Great Gatsby, we think of the final few lines, Gatsby staring at the light at the end of Daisy’s dock, etc. more than anything else about it.
Motifs can be images, like the light I mentioned above in Gatsby, or objects, like water in the same novel. Motifs can also be phrases or words that are repeated, like the line “So it goes.” in Vonnegut’s Slaughterhouse Five, or a technique, like the retelling of scenarios, as used in The Things They Carried, in which O’Brien doubles back and retells the same handful of scenes from different characters’ perspectives.
Morifs should develop as naturally as possible; just be on the lookout for opportunities. Again, not every story needs motifs, but I do think every story needs some higher-level element, which is usually a form of symbolism. Motifs are often somewhat subtle, though not always. And Motifs should be essential; don’t make a Motif just for the sake of having one. As Chekhov famously said, “If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it absolutely must go off. If it's not going to be fired, it shouldn't be hanging there.”
Symbolism can be overwrought and distracting, of course. Personification is one of the worst offenders. Similes can frequently accomplish the opposite of the author’s intent; similes are supposed to give a comparison that helps define something that’s difficult to define by describing it using the qualities of something else, but it can easily shift the reader’s attention over to that other thing. Metaphor can do the same. Symbolism should be subtle to keep it from distracting the reader from the actual story. Some symbols have cultural significance and because of this are clichés. A dove, for example, represents peace; we all know that. But why does it represent peace? When a reader sees a dove in a story, they think, “That represents peace.” There is no Ah ha! moment and no real deepening of understanding in the story. The image is so familiar it’s meaningless. If anything, the reader is put off because they’ve encountered a cliché, which shows poor writing.
Again, it’s about the reader’s enjoyment of the piece, and these elements like motif, symbolism, and themes, when handled well, give the reader opportunities to be active (by noticing and then figuring them out) and give you, the writer, opportunities to tell the reader what to think without alienating them.