This sentence has five words. Here are five more words. Five-word sentences are fine. But several together become monotonous. Listen to what is happening. This writing is getting boring. The sound of it drones. It’s like struck record. The ear demands some variety.
Now listen. I vary the sentence length, and I create music. Music. The writing sings. It has a pleasant rhythm, a lilt, a harmony. I use short sentences. And I use the sentences of medium length. And sometimes when I am certain the reader is rested, I will engage them with a sentence of considerable length, a sentence that burns with energy and builds with all the impetus of a crescendo, the roll of drums, the crash of the cymbals–sounds that says listen to this, it is important.
So write with a combination of short, medium, and long sentences. Create a sound that pleases the reader’s ear. Don’t just write words. Write music.
by Gary Provast, 100 Ways to Improve Your Writing