I recently learned there is such a thing as a run-on paragraph. Whenever I write stories my paragraphs become a page or longer at times, so I began to wonder if I make run-on paragraphs. I haven't been able to find much information on it, so I came here. Can someone please explain to me what a run-on paragraph is?
Every once in a while you must give your reader permission to take a break from your stream of words for the purpose of processing the meaning—figuring out what it is, and whether he or she agrees. Among the permission-giving signals, in increasing order of magnitude, are comma, semicolon, sentence break, paragraph break, new section heading, and new chapter heading. Being too stingy with any leads to reader fatigue. Being too stingy with paragraph breaks leads to the specific kind of reader fatigue that generates accusations of “run-on paragraphs.”
A "paragraph" (as "officially" defined) is supposed to consist of one or more sentences -- one "topic" sentence (usually the first), and zero or more additional sentences which expand on the topic. The last sentence (when there are several) will often be a "concluding" sentence which sort of "wraps up" the topic.
Breaking a long body of text into paragraphs serves first the writer, as he must consider how the discussion is to be structured and "outline" it, either in his head or on paper. Then the paragraphs serve the reader, first by simply providing visual "handles" on the page/screen so that the eyes do not lose track of where they were last reading (especially important on a screen), then by presenting the ideas of the writer to the reader as coherent "thought packages" which can be read and internalized one at a time.
However, there are (outside of prescriptivist college English courses) no "hard" rules about paragraph structure -- it's largely a question of what serves best the communication process between writer and reader.