Have you ever read a script treatment for a play or movie? If you have, you've probably noted that not much time gets wasted describing things. The key to a good script is to give the basic idea, and then let the talented moviemakers—the director, cinematographer, and producers—fill in the blanks. Here's a classic example from Arthur Millar's phenomenal The Crucible:
Proctor, with a grin: I mean to please you, Elizabeth.
Elizabeth—it is hard to say: I know it, John.
He gets up, goes to her, kisses her. She receives it. With a certain disappointment, he returns to the table. (Act II, Scene 1)
Short, sweet, but it gives you all the detail you need to see how things will play out on stage.
Now a sample from Asimov's Foundation:
The waiting spaceship bulked somberly in the dimness. Hardin stamped through the snow toward it and at the open air lock turned about with outstretched hand.
"Good-by, Lee. I hate to leave you in the frying pan like this, but there's not another I can trust. Now please keep out of the fire."
"Don't worry. The frying pan is hot enough. I'll follow orders." He stepped back, and the air lock closed. (III.5.29-31)
Yep, short and sweet. Asimov, like Miller, uses active verbs in short sentences to align his characters and then lets them speak. Like a play, the speaking is where the characters really come to life and so a lot of page space is dedicated to conversations.
And like a play, the reader—that's you—gets to imagine how everything will look in the final product. Only instead of one person doing set design, costuming, makeup, and so on, you get to do it all free of pay. Which can either be thrilling or terrifying; your call.