There’s an old saying that goes, “If you aim at nothing you’ll be sure to hit it,” meaning, of course, that you must have a specific goal in mind when performing any task.

That’s good advice for writers. We must aim at something, that is, we must have a purpose for writing. Without a clear-cut purpose, you won’t know if you’ve accomplished what you’re trying to do for your readers.

This article works through a simple three-step process to create a detailed purpose. We’ll use the topic of how to invest in the stock market.

Here are the three steps:

1. Determine why you’re writing

From the reader's standpoint, there are just four reasons for writing. They form an acronym: PIER

To Persuade

To Inform

To Entertain

To Remind

Think about anything you read or hear. It will fall into one of those categories. The evening news? To inform. TV sitcoms? To entertain. A car dealership's commercial? To persuade. Of course, much writing covers two or more of those reasons. A political candidate sends a flyer to persuade you to vote for her and to remind you to go to the polls.

Let’s take one of those four reasons and use it to create a specific purpose for writing. We’ll use persuade.

Now on to the second step.

2. Add a description of your audience

Think of a detailed picture of your readers. Who is your target audience? Remember we’re working with a topic of how to invest in the stock market, so are your readers young adults just starting as investors? Middle age empty-nesters who are starting to think about retirement?

Furthermore, how knowledgeable about investing is your potential audience? You'll approach your work differently if your readers are novice investors than if they have a working knowledge of the topic.

We’ll say our audience is young adults, so now we have:

We’re writing to persuade young adults . . .

3. Add an action phrase

The action phrase is your topic or a slight variation in the wording of the topic. So, with our topic of how to invest in the stock market we put all three parts together and have this:

We’re writing to inform young adults how to invest in the stock market.

Notice how crystal clear your purpose is. Now you know exactly why you are writing.

Whatever your reason for writing, here is a critical point—make sure you don’t depart from it. Every sentence you write must relate to your purpose. Otherwise, your story will be poorly organized, disjointed, and difficult to understand.

So before you put your hand on a keyboard, decide why you're writing. Then stick to it.

If you’re writing fiction, this same principle works. Perhaps your story is about a young woman living in the South during the Civil War. She meets up with a wounded Union soldier, compassionately cares for him, and they fall in love. Your purpose might be “to entertain my readers with a tale of love and compassion set during the Civil War. Again, now you know exactly why you’re writing and that gives you a solid framework to write with.