Read any student essay, and you're likely to get abstract descriptions: The vacation was "wonderful" the food tasted "great," and the dog was "cute." When we ask students to add more detail, or be more descriptive, we often get lists of adjectives. What we really ought to be asking for is concrete detail, or sensory detail.
I use this example for the class: "If I went on a roller coaster and told you it was 'thrilling' or 'terrifying,' what does that tell you?" The students won't see what I'm getting at here. They usually think it's a fine explanation. Then I say, "What if I told you that I was holding on to the handle so tight my knuckles were turning white and my fingers went numb? I could feel sweat forming on my neck and hairline. I could taste the pink cotton candy I'd eaten earlier in the back of my throat when I opened my mouth to scream." Now they begin to get it. I pause for a minute to let them think about it, then say, "In the first explanation, I TOLD you what it was like, the second explanation let you EXPERIENCE what happened because I used sensory details. Which is more powerful?"
When talking about the difference between abstract details and concrete details, I usually explain it by asking if I can see it, feel it, hear it, taste it or smell it. If the answer is no, then it's probably not concrete detail. It's effective to make a list of overused abstractions such as wonderful, exciting, and awesome, then list how we might show this instead. During revisions, I have students identify at least three places where they could add sensory details.
Another method to help students think beyond the obvious and overused for their details is teaching them figurative language. When writing a narrative essay in the first few weeks of the quarter, I require them to use at least one of the following: metaphor, simile, hyperbole, personification or allusion. To practice this, we go over each one, and then I have students work in groups to come up with one of each for a piece of artwork to share with the class. My students are usually a little unsure of themselves in writing figurative language, but doing it with a group first makes it fun and often leads to some profitable discussions.
I knew I'd gotten through when a student started with "the singer was wearing a long yellow jacket and sang to the large crowd" and ended up with "the singer looked like a giant, sweating banana rocking out in front of a horde of hungry ants." It's not exactly Proust, but the image made me smile, and it was concrete.
A full lesson plan for the figurative language group activity is in my store here. Here are two descriptive writing freebies to use with your class: