It's as easy as falling off a log, he was faster than greased lightning, she was slower than molasses.
All of these statements have something in common. They are all ways to illustrate a quality of someone or something.
It's been said that a picture is worth a thousand words. If you've ever tried to assemble something that you purchased in pieces, such as a bookcase or other piece of furniture, you can appreciate the truthfulness of that statement. Even if the directions are in Japanese, seeing a picture or simple drawing can make the necessary steps clear (or at least clearer). In the same way, pictures make a valuable addition to practically any form of writing. However, in many cases, pictures are just not an option. At these times you'll have to rely on another resource, your skill as a writer. Can you paint a picture with your words? Can you make your reader feel the blizzard? Smell the freshly baked bread? Or see the sunlight sparkling on the icy gurgling water of a mountain stream? In your non-fiction writing, can you help your audience understand and appreciate the significance of the point you are trying to convey? Word illustrations are an important tool to help you accomplish these goals.
Illustrations are figures of speech, real-life experiences, or stories that help your reader visualize what you are trying to say. They not only make your writing more interesting, but they can also aid in retention and understanding. For example, think of "The Boy Who Cried Wolf" or "The Tortoise and the Hare," both part of "Aesop's Fables." Each of these stories teaches a lesson or contains a moral. The stories illustrate the principles being taught in a way that makes them obvious and easy to remember. In fact, the expression "crying wolf" has become an English idiom.
Real-life experiences, or true stories, can be even more effective at illustrating a point. For example, to illustrate the idea of never giving up, you could point to Thomas Edison. His teachers thought he was too stupid to learn anything and he was fired from his first two jobs for being non-productive. Although he is famous for inventing the light bulb, did you know that he failed in his first 1,000 attempts? For a simpler example, you could mention that Henry Ford failed and went broke five times before he succeeded.
Of course, in many forms of writing, there is no room for a long story, whether true or not. This type of illustration would be out of place. It would be like seeing a gold nose ring in the snout of a pig, or about as welcome as ants at a picnic. But don't worry! The simplest, and sometimes most effective, way of painting a picture with words is to use a figure of speech. The simplest of these is the simile. As you might guess, the word simile comes from the same Latin word as similar, a word that means "like." When you use a simile you are saying that one thing is like another, or "as" another (see the two similes at the beginning of the paragraph). Most of us use similes all the time in ordinary conversation, perhaps without even thinking about it. If you've ever said that someone was as big as a house, as fat as a pig, or as dumb as a stump, you're not very nice. But congratulations! You know how to use similes.
Metaphors are similar to similes, but metaphors make a stronger comparison. Instead of saying that one thing is like another, a metaphor says that they are the same. When Shakespeare said that all the world's a stage and all the men and women merely players ("As You Like It" Act 2 Scene VII), he was using a powerful metaphor. You too can use metaphors to give a powerful impression or make a strong point, perhaps changing a good simile into a better metaphor. For example, you might say that someone is as courageous as a lion. This is using a simile to pay them a nice compliment. You could make it a nicer compliment by saying that the person has the heart of a lion.
However, with both similes and metaphors, you have to be careful that your readers don't get the wrong meaning. For example, if you state the above metaphor in a different way, the meaning changes. If you just say that the person is a lion, are you still paying them a compliment? Or are you saying that they are fierce, or prey on the weak, or scare small children? In the same way, to be as cautious as a snake is good; to be a snake may not be so good. So then, metaphors can be used to make strong points, but to be effective you have to make sure that they are unambiguous so that your readers clearly understand what you mean.
You might also use hyperboles in your writing. These are deliberate exaggerations. For instance, if you said that your wife's coffee was so strong that you could float a horseshoe in it, you would be using hyperbole or exaggeration (hopefully). Like metaphors, hyperboles are very effective at making strong points but can be easily misunderstood.
This brings us to our final point. Whatever word picture we paint, whether through the use of a story, simile, metaphor, or hyperbole, it's valueless if not understood. In fact, it may be worse than valueless; it may detract from your story or confuse your reader. How do you make sure that this doesn't happen? First, consider your audience. Using a humorous story based on quantum mechanics (I know it's tempting) as an illustration may be perfectly acceptable when writing for a group of theoretical physicists; for others, it may be less effective. As with many areas of life, it's usually best to keep it simple. Try to find figures of speech or stories that the majority of people can readily understand and identify with. Generally, this means using comparisons that involve ordinary things that affect people's daily lives, such as the weather, family life, the work environment, common foods, etc.
Like pictures, diagrams, or charts, word illustrations can be used to add color and variety to your writing. Yet they also do much more. Used properly in a fictional story, they can add richness, depth, and texture to the picture you're painting in the reader's mind. In other forms of writing, they can improve your reader's retention and understanding of the points you are trying to convey.