Photography, as any other form of art, has the capability of transmitting what would be worth a thousand words and diverse feelings. It is a concept that can be very easily experimented with: colour can be graded, subjects can be shifted, and ideas can be modified. It is a matter of having an eye out on visuality. Before you begin experimenting with the secondary aspects of developing a visual, photographic storyline, make sure that you understand the basic and primitive stages of preparing an image. You can read more about that here.
A popular effect among the creations of visual artists is the use of grain. This is an easy filter that is applied as the very last stage in the editing of a photograph. It is a mood enhancer, which usually creates a tumblrish atmosphere (and by this I also mean slightly nostalgic, historic, and storytelling, chiefly).
At its most basic, Wikipedia states that film grain is, “Film grain or granularity is the random optical texture of processed photographic film due to the presence of small particles of a metallic silver, or dye clouds, developed from silver halide that have received enough photons. While film grain is a function of such particles (or dye clouds) it is not the same thing as such. It is an optical effect, the magnitude of which (amount of grain) depends on both the film stock and the definition at which it is observed. It can be objectionably noticeable in an over-enlarged photographic film photograph.” (Chris Gampat)
I edited the following images in Adobe Photoshop Lightroom CC which allowed me to not only apply grain to my images but also to choose the size of the grain as well as the intensity of it. This, as a result, helped me decide precisely the mood I wanted to send off through my images. A way to remember it is that the stronger the grain effect, the more historic and enigmous the image looks; it will look as if there is an in-depth backdrop of a story. Similarly, the less grainy an image look, the more modern and direct it can seem. Of course, however, there will always be loads of underlying factors that determine the symbolism of your photographs (for instance, black and white portraits can tend to look profound).
A crucial element of grain is that not all pictures can carry it well towards an audience. In fact, many viewers will criticize it for ruining the quality of the image itself. Others will assert that it completely deteriorates the entirety of a story behind a photo by being such a simple filter that anyone can easily apply to their own photos. Essentially, it is a risky effect and sometimes pictures will look a lot better left as they are originally.
In the end, it is up to you solely. Grain can undoubtedly emphasise the story behind an image, yet it can also very quickly alter it into one that is utterly different.