If you "tell" me something when you write a poem, I'm perhaps learning, but not feeling. A newspaper article that explains details of an event expose the facts but not the soul nor the catalyst to explore your own. Make a "Purple Haze" of your own invention so I can "Kiss the Sky"?! Save your telling poems for a Mother's Day card. (They do have a wonderful purpose)!
While tell consists of affirmations, show resides in showing the lyrical voice in action. When you tell something rather than show it, you just inform your reader, instead of permitting them to experience the essence of a stanza.
modified snippets from my fantasy Dreamlander (affiliate link).
Telling:
Orias ran away from the soldiers. His horse jumped a fallen tree branch. He heard someone shout for him to stop, and he felt nervous. The soldiers halted and aimed their rifles at him.
Showing:
From behind came the pounding of hoofbeats. Tree branches whipped across Orias’s face and showered his saddle with leaves. He gritted his teeth, his face set in the snarl that had become his protection against an unjust world. They would not catch him. Must not catch him.
He spurred his horse’s bloodied sides, and his fingers itched to reach for the broadsword sheathed on his back. His blood thundered in his veins, pulsing against the oyster white of his skin, sharpening his reflexes, narrowing his thoughts to razor intensity.
His tired horse stumbled, and the hoofbeats behind drew nearer. Voices shouted: “Stop now! In the name of Mactalde, surrender!”
He spat an oath and ducked another tree branch. Even the man’s name—dead though he was these twenty years—burned through the air like a curse.
Hoofbeats slowed and faded, surpassed by the rapid clatter of rifles rising to aim and the click of bolts locking into place. Orias’s blood congealed in his veins.
The difference, of course, is immediately discernible. The first example gives the reader the necessary facts, but the second brings those facts to life.
The Difference Between Showing and Telling
When you tell rather than show, you inform your reader of information rather than allowing him to deduce anything.
You’re supplying information by simply stating it. You might report that a character is “tall,” or “angry,” or “cold,” or “tired.”
That’s telling.
Showing paints a picture the reader can see in her mind’s eye.
Here’s how to show and not tell:
If your character is tall, your reader can deduce that because you mention others looking up when they talk with him.
Or he has to duck to get through a door. Or when posing for a photo, he has to bend his knees to keep his head in proximity with others.
Rather than telling that your character is angry, show it by describing his face flushing, his throat tightening, his voice rising, his slamming a fist on the table. When you show, you don’t have to tell.
Cold? Don’t tell me; show me. Your character pulls her collar up, tightens her scarf, shoves her hands deep into her pockets, turns her face away from the biting wind.
Tired? He can yawn, groan, stretch. His eyes can look puffy. His shoulders could slump. Another character might say, “Didn’t you sleep last night? You look shot.”
When you show rather than tell, you make the reader part of the experience. Rather than having everything simply imparted to him, he sees it in his mind and comes to the conclusions you want.
What could be better than engaging your reader—giving him an active role in the story experience?
Examples:
Telling: When they embraced, she could tell he had been smoking and was scared.
Showing: When she wrapped her arms around him, the sweet staleness of tobacco enveloped her, and he shivered.
Telling: The temperature fell and the ice reflected the sun.
Showing: Bill’s nose burned in the frigid air, and he squinted against the sun reflecting off the street.
Telling: Suzie was blind.
Showing: Suzie felt for the bench with a white cane.
Telling: It was late fall.
Showing: Leaves crunched beneath his feet.
Telling: She was a plumber and asked where the bathroom was.
Showing: She wore coveralls, carried a plunger and metal toolbox, and wrenches of various sizes hung from a leather belt. “Point me to the head,” she said.
Telling: I had a great conversation with Tim over dinner and loved hearing his stories.
Showing: I barely touched my food, riveted by Tim. “Let me tell you another story,” he said.
Please make it a point to study and internalize this, it is perhaps the most important lesson in creative writing. Personally, a poem that "Tells" me to perfection, that is perfectly rhymed/metered & formed, has no chance against a poem that shows me seductive & thoughtful emotion.