A key piece of advice many writers either do not ever get or don’t believe is that it’s not necessary to write introductions first. Just because the introduction appears first doesn’t mean it has to be written that way. Here’s a really tired metaphor to help explain: just because you walk into a building through the door doesn’t mean the door was built first. The foundation went in first, even though you rarely if ever see that part. And lots of imperfections in the foundation and the walls were covered up before you even moved in, so you can’t see those either unless you look closely.

Even though a nearly infinite number of topics and arrangements is possible in English prose, introductions generally follow one of several patterns. If you’re writing a children’s story, you’d probably start with “once upon a time” or something similar. If you’re writing a research article in biomechanical engineering, you’d probably start with a statement about how previous research has examined the problem of loading soldiers with daypacks on various surfaces, including sand, concrete, and railroad ballast. These examples are poles apart, but their introductions share very similar purposes: they orient their imagined readers to the topic, time, and place.

In working toward the overall goal of orienting readers, introductions may

• Provide background about a topic.
• Locate readers in a specific time and/or place.
• Start with a compelling quotation or statistic—something concrete.
• Include an ethical appeal, with which you (explicitly or implicitly) show that you’ve done your homework and are credible.
• Articulate a main claim/thesis.
• Lay out the stakes for the piece of writing—that is, why the reader should bother reading on.

The following video addresses how to do several of these things, starting with the very first sentence of your introduction.