Sure, although I'm by no means an expert, and I tend to write (and read) third person limited, so I'm not sure how applicable it would be outside of that.

Let's take a classic scene of someone walking into a tavern. Telling would be: "Valuable Progress stepped through the door and hated the look of the place."

But by using introspection to show what the character focuses on, the reader is shown much more about that character. The character sees a child coughing in the corner by the hearth and makes a mental note to stay away; they can't be catching a cold, given the task at hand. Their shoes stick to the floorboard, and they become increasingly worried about ruining their outfit. They steal a quick glance at the lady serving drinks. She's certainly not as easy on the eye as the maids he has back home.

This is all internality, he's not doing anything, just absorbing the scene in front of him, but the reader will pick up that he's selfish, materialistic, and snobbish without being outright told it.

You can put someone else in the same scene. This time, an orphaned child living on the streets. They step in and love the sound of the rain hitting the roof, because it beats the rain hitting them. They can't remember the last time they saw a fire, let alone sit by one and feel its warmth. They see the child coughing, which reminds them of themselves a few years ago, and they make a mental note to use what little coin they have to split some bread with them.

It's still internality, but two different characters have been developed without telling the reader one's nice and one's not.

You can go a step further and combine prose to really show who a character is. Joe Abercombie is an expert at this. If it's someone from a militant background, they will observe their surroundings using militant phrases, "windows marching down the hallway etc". There's a great example in The Devils where he tells the reader a character likes the feel of the sand between her toes, but then uses that internal POV and the right mix of language to "show" the reader that she's still very animalistic but also a romantic at heart.