Is there a formula or certain way that one may find the theme in a short story? A step by step route that's easy to understand and guides the...

I am not aware of a single formula or procedure that can
be applied to identify the theme in all short stories, largely because there is so much
variation in short stories. The differences in structure and presentation between
stories makes it extremely difficult to apply the same route to all the various
possibilities.

Because short stories are, by definition,
not lengthy, they don't have the luxury of long explanations or introductions of setting
and characters. Most short stories tend to present important elements fairly succinctly,
which should help with the isolation and identification of those items. When looking for
the theme, the reader needs to be searching for the common factor - the idea or motif or
emotion that recurs throughout the story. If the reader can find that base point to
which all the action keeps returning, the reader has found the theme of the
story.