Discovering how to write description can also hinge on your viewpoint as the writer. If you're the type that tends to visualize whatever sequences you're writing, then all you need to do if you feel the need for description is mentally pause the scene and rotate the camera to take a closer look at the surroundings. If you're not the visualization type, then, with the understanding that your characters understand the world as your readers would (not always a given in sci-fi), ask yourself some sensory questions. Around the characters, what are the colours? Shapes and angles? Textures? Odours? If need be, jot down the answers quickly, like a bullet-point list, then find a way to turn them into a sentence or two.
Personally, I've always found the most difficult aspect of description to be balance. On the one hand, you want to prove the readers with an idea of the character's surroundings; on the other hand, you don't want to bog the reader down with long, unnecessary itemizations of their physical environment. This is particularly important in short stories, where the brevity of the story means space is already at a premium, and scenic material competes with plot, characterization and the rest of it for words on the page. I know I get annoyed when reading someone like Chekhov, who sometimes spends half his story making landscape paintings, or Zola, who is compelled to give the history behind every damn spot on the wall. IMHO, description is best used sparingly where it isn't important for the reader to understand the physical layout of the scene. Unless, of course, landscape plays an important role in the story, which is a strong possibility in a sci-fi context where landscapes might be unfamiliar or otherwise radically altered. Hmm; I don't think this is helping. Basically, whatever the story requires.
Fictitiously yours, Trent Roman
