Vary Your Sentence Length and Structure
Why it's important
If you've ever read an article in an academic journal, you might have noticed that the sentences are almost always long and complex. Other types of writing, such as news reports, tend toward shorter, more direct sentences.
In general, your writing is most compelling when you vary the length of your sentences. Too many long sentences in a row will put readers to sleep, but too many short sentences make your writing feel choppy and simplistic.
Example:
The passage below is taken from Mark Twain's "A Ghost Story." Notice how Twain builds suspense by varying his sentence length, creating a rhythm between tense waiting and sudden action.
The fire had burned low. A sense of loneliness crept over me. I arose and undressed, moving on tiptoe about the room, doing stealthily what I had to do, as if I were environed by sleeping enemies whose slumbers it would be fatal to break. I covered up in bed, and lay listening to the rain and wind and the faint creaking of distant shutters, till they lulled me to sleep.
I slept profoundly, but how long I do not know. All at once I found myself awake, and filled with a shuddering expectancy. All was still. All but my own heart -- I could hear it beat. Presently the bed-clothes began to slip away slowly toward the foot of the bed, as if some one were pulling them! I could not stir; I could not speak. Still the blankets slipped deliberately away, till my breast was un-covered. Then with a great effort I seized them and drew them over my head. I waited, listened, waited.
Varying sentence length helps keep your readers' interest no matter what kind of writing you're doing.