One way to show imagery is through figurative language. Figurative language includes similes and metaphors.
A simile compares two unrelated things using "like" or "as."
A metaphor compares two unrelated things without using "like" or "as."
Example:
Simile: "Her desire was like fire"
Metaphor: "Her desire, a fire"
Based on the last chapter about avoiding clichés, you'll know that this example shown above is cliché. Love/desire is often compared to fire.
It's tricky to avoid clichés since they're so ingrained in our minds. For example, if I say, "Stiff as a _____," you probably just filled in the blank with "board." This is a common simile. Anything that's predictable like this you'll want to stay away from.
So, how do you avoid clichés?
The best similes and metaphors compare two things that usually aren't expected by the reader. It may take some time to create unique similes and metaphors of your own. With practice, however, you'll be able to create them with ease.
Exercise: Turning unoriginal clichés into something new
Make a list of clichés that come to mind, then pick apart each one, replacing the common words with something unique while maintaining the meaning of the line.
For example, let's use "cold like ice."
Now, brainstorm what words could replace "ice" and make a list.
-stone
-winter
-night
-snow
-a freezer
(Keep in mind that the first things on your list may not be the most original, as you can see here. However, as you keep brainstorming, you'll find that the farther down the list you go, the more unique your ideas will become.)
-a cellar
-a gravestone
-a temple (instead of using "stone," I'm trying to be more specific)
(I'm going to stop here. If you'd like, you can continue expanding the list, but I have enough written down at the moment to use for this example.)
Now that you have your list, start replacing "ice" with some of the words you've come up with.
I'm going to go with "cold like a cellar." It doesn't seem like much, not yet, anyway. This gives the reader a vague image of a cellar, and we can assume it's cold. But, if you want to create a simile that has stronger imagery, you'll want to expand on it.
For example, "cold like the cellar buried beneath the abandoned house" or "cold like the cellar littered with broken bottles." By expanding the simile, you're painting a stronger picture in the reader's mind. You can even take it a step further by adding a few more lines of description to it. Before you know it, you could have an entire stanza built around that one simile.
This exercise applies to metaphors as well.