I've answered this often at another writing forum I visit. Let me go find a recent time and copy-and-paste... [sound of receding footsteps]
TELLING VERSUS SHOWING
This is a favorite theme for English teachers to harp on, but not very many of them can really make student writers understand the difference. Technically, there’s nothing wrong with just stating the facts.
Usually Maggie was one of the first ones to leave, but today she was late because she was having trouble pinning her shirt where the button had popped off. The girls didn’t notice that she was still getting dressed when they left the locker room, talking. She heard Jodie Brennan say that Maggie should be cut from the volleyball team because she couldn’t jump high enough to touch the top of the net. Since she hadn’t had a choice about being short, it hurt her feelings. (86 words)
OK, we know what’s going on—but do we care? Do we like or dislike Maggie, or Jodie? If you’re writing fiction, you have to make the readers feel something about the characters you create. You do that by showing what’s significant.
Maggie winced and sucked at the bead of blood on her thumb. Why did she have to lose a button today? She was running so late. She’d just pushed the pin through a fourth time—still crooked—when she heard Jodie Brennan.
“Maggie? Shrimp shouldn’t even be on the team. Even jumping, she can’t touch the top of the net!”
The pin forgotten, Maggie felt her face heat. She didn’t choose to be short—it just happened. Like Jodie’s crooked teeth. Maybe Jodie shouldn’t be allowed in Choir! (88 words)
As you can see, it takes a few more words to show, but it’s usually worth it. Now we don’t like Jodie and feel a little sorry for Maggie even though she’s spiteful.
Often, the difference between showing and telling is the difference between stating observable facts and allowing the reader glimpses into the head and/or heart of the POV character.
I have a couple other examples. Let me hunt them and I'll edit them in.
Maryn, who struggled with this for ages
Edit to Add:
These are telling:
Juan looked at himself in the mirror. His little brother pounded on the bathroom door, and Juan yelled at him to use the other bathroom. Juan wondered if his big brown eyes were sexy. His upper lip showed where his mustache would be, but something was wrong with his hair. Usually he was proud of his thick, shiny hair, but today it was lopsided, with a high, puffed-up spot on one side.
Benucci ran for his life. For the first time, he wished he’d exercised like he knew he should have. He panted for breath and felt himself slowing, not getting closer to the woods very fast. If he didn’t reach the cover of the woods, a bullet would find him.
This is showing:
Juan studied his reflection despite his little brother’s pounding on the closed door. “Use the other bathroom, Ramon!” he yelled, his eyes never leaving the glass. Good eyes, big and brown—sexy?—and the hint of a mustache-to-be, but what was wrong with his hair? Usually he had good hair, thick and shiny as his sister’s, but today one side looked like he’d hidden a Nerf football under there.
Benucci ran like he hadn’t since junior high. Why had he let himself get so soft and slow? He gasped, his lungs burning, his legs rubbery, the woods and cover still far away. Ironic, that he was about to be shot because he didn’t join the YMCA!