let's get this straight: i still have problems with this. it's hard to remember to do this. but try your best.

in the realm of literature, showing your audience something is far better than telling it in a long waxing paragraph.

showing can be achieved by context clues and background details! dont tell how the moon was shining, show us the light glistening on broken glass.

lets have an example, since it's easier to see this way:

"Catherine," the man murmured, a heavy tone in his voice, "It's your father. He's died."

Catherine grimanced. For years, she had put up with her father's drunken beatings, but now, it was all over. She felt free.

"He deserved it," Catherine snarled.

Now, how about we show those facts instead?

"Catherine," the man murmured, a heavy tone in his voice, "It's your father. He's died."

Catherine grimanced, years of emotions finally bubbling to her surface. She rubbed her arm. The physical scars he left her might have healed, but the mental ones would remain raw for the rest of her days. But, beneath all the pain, there was hope, an airy relief of the weight that had been on her shoulders all her life.

Catherine's expression hardened. "The drunk deserved it," she murmured without pity.

Now, which one sounds better? They both work, yes, but the showing example feels a little better, no?

Instead of flat out telling the audience that she was abused by her drunk father, I showed you the emotion she felt. I showed you the scars she had. I showed you that she felt free. 

I was once scolded for telling way too much in an early fanfic of mine. The person (who i am still thankful for) told me that, instead of simply saying it in narrative that my character had a family he dearly cared about (it was to humanize him), that i could include a scene where he comes home to his family and sees his kids.

Showing also forces you to be clever and inventive in your narration. Now that you know its frowned upon to simply info dump everything, you will be more inventive in your descriptions and such.

Showing and be really really powerful, and more poignant than telling. Simply telling us your character has an abusive past isn't quite as good as showing us the cigarette burns on their back.

"It was cold outside" vs "Chillbumps ran down Victor's back, numbness traveling through his fingers"

"He was happy" vs "A gentle smile touched Umbra's lips, and his cheeks became warm as he gazed at Matthew"

"Victor was afraid of thunderstorms" vs "With every boom of thunder, Victor's heart grew more and more frenzied. He had locked himself in the closet of his room, hoping to muffle the noise. He hid his head between his knees, ugly sobs wrecking through his frame"

Now, not everything can be shown. Sometimes informative sentences are needed. And that's okay!

Show vs tell is pretty hard to keep up. It requires a conscious effort on your behalf. I still havent mastered yet.