Writing science fiction isn't all that hard. You just need to have a list of words that usually appear in science fiction stories, and use them to replace words in a more mundane story.
For example, let's take a short story about a guy named Ted, who's going to the hardware store to buy parts to fix his lawn mower. The SF replacement words will be in parenthesis.
It was Saturday. Ted got into his (rocket ship) and (warp jumped) over to the (space station) on (L4). Entering the (microgravity zone), he asked the (mutant) behind the (computer terminal), "I need some (radioactive) (positron dampers) for my (ray gun). Where would I look?"
"Try the (torus)," the (mutant) replied with an affable smile. "If you don't see any there that will fit, you can ask Bob. He's our (alien from Proxima Centauri). He should be able to fix you right up, Ted."
"Thanks, Jim," said Ted, and (floated up the access tube) into the (torus) section of the (space station). He found Bob, an older, pleasant-looking (creature) with thick (chitinous shells) over his eyes, and a bristle of (tentacles) under his nose, and asked him about the parts for his (ray gun.)
"What model is it?" Bob asked him, and after a little thought, Ted replied, "It's a (2886 Megatron Ultra-Dissipator with a Borgenstein Reactionary Overload Isometric Isotope Confibrillation Drive). I know, I know, it's a little on the old side, but it's served me well, and she runs like a top most days. It's just that it's spring and I need to put in a new (positron damper.) The old one's all crusted up with carbon deposits. I promised my neighbor I'd bring it by his place this afternoon."
Bob nodded in understanding, spat a stream of (acidic digestive juice) into the Mountain Dew bottle he had with him, and led Ted over to a rack of (positron dampers.) He poked through the boxes with his (cybernetic hand) and came up with one that he told Ted would "do you up fine."
Ted thanked old Bob, and went back to the (microgravity area) to pay for his part.
"Find what you were looking for?" asked Jim, the (mutant). Ted nodded and put the box down on the (computer terminal,) where it was (scanned) and the total appeared.
"Fifteen (credits?)" Ted exclaimed, "For that thing? Why, that's (hyperspace) robbery!"
"I know, I know," agreed Jim, "but the prices of parts have all gone up, with the new EPA restrictions. They're trying to phase out these things. In a couple of years, you'll be lucky to be able to find parts for the old (ray guns) at all, if this keeps up!"
Ted grumbled, and grudgingly (pressed his thumb to the biometrics reader) to pay for his part. "I may need to buy a second one, just to have the parts available," he said as the (mutant) bagged his order for him. "It would probably be cheaper that way."
Ted got back into his (rocket ship), still thinking about how much things had changed since he was a youngster, and (warped) back home, where he replaced the (positron damper) and spent the rest of the afternoon mowing his neighbors down.
See? It's that easy! You can read it as a SF story, or you can imagine the real-world words that I've replaced, and get a simple little tale of a guy who wants to fix his lawn mower so he can--
Oh, hold on a moment...
Oh, sorry, that should have been "lawn." Mowing his neighbor's "lawn."
Amazing, what a difference a word makes, isn't it...?