Sci-fi and fantasy can be daunting genres to a writer who wants to test the waters.  Creating your own world, your own society, as a backdrop to a story, can appear an immense task.  So, where do you start?  Define your setting.  Am I doing (1) another planet, (2) a fantasy reality, or (3) our own contemporary world with an injection of fantasy elements?  The last is easiest, needing the least amount of invention.

There are some general choices you need to make: 

Cultural sophistication: are you using a high-tech world, contemporary world, or primitive low-tech world.  In other words, will I be describing people walking, riding animals of some kind, or mechanisms of some sort.  You can even have an overlap.  You can have alternate worlds with elves, dragons, wizards, and advanced technology.  The neat thing about using your own world is that it’s how you make it.  No one can contradict your facts.  You just have to be logically consistent in the elements you use.  A world with trains needs steel forging technology and coalmines.  Gunpowder may be optional.  The more technology, the more of an infrastructure you need for it.  Fortunately, you don’t have to show all that.

Tunnel Vision: You don’t have to provide the reader with an in-depth background, world history, and culture as part of the setting.  You can leave out much of this.  Just ask yourself, “What elements are going to enter the perceptions of the main character?”  Use that character’s POV (point of view) as a narrow window to your new reality.  The only part of the setting you need to show is the part your main character will directly experience.  The only part of the alien culture you need to reveal to the reader is that part that directly effects the main character's present circumstances.  

    He will perceive the world around him through his senses.  Therefore…make a list of natural elements you want to briefly highlight: What color is the sky?  The sun?  Is there more than one sun?  The grass?  Are there unusual plants that will stand out?  Is this in a jungle or forest?  Am I setting my story in a mountain area?  Seashore?  A swamp?  Deciding on the climate and the time of year will give you a good idea as to the type of clothing your characters will need. 

A rose by any other name: The heart of a story will always be conflict.  You can approach your other-world characters as if they are very human, regardless of what they look like.  All living things are going to generally share the same basic animal needs: sex, food, shelter, and clothing unless they have tree-bark skin or scales or something.  Other desires that drive people can also drive aliens, or humans in a fantasy world.  The desire for companionship, power, accomplishment, revenge, are still driving forces.  Love itself is a universal force. 

Try telling your story as if it weren’t sci-fi or fantasy, just another story.  Then go back and put your own spin on all the elements of setting and culture.  Don’t so much write a fantasy/sci-fi story as transmute one into that form. 

Start with a “normal” conflict: how about parents arguing over what’s best for their child, and the kid being caught in the middle?  Happens all the time right?  Well, this happens in sci-fi and fantasy too.  It’s the story of Star Trek's Mr. Spock, for instance, with his Terran mother and his Vulcan father.  Remember, there’s no such thing as an original plot—-only original variations on them.

Example:

         FIRST TRUTH

Mom and Dad were at it again. 
     "How can you do this to your own son!?!" Momma shrilled. "Let the boy eat SOMETHING. It’s been three days." 
     "You know my answer," that was dad, his quiet voice deep as a grave, filling the room. "It’s his fifteenth summer. If he is to have a place on this world, he must be more Edothican than those of full blood. I cannot excuse him from the Rhi’kah. He must prove his understanding of First Truth."
     That’s right. Talk about me as if I’m not in the room... just forget I’m here...
     I drew a cautious breath, and felt a sharp pain in my side. I was pretty sure I’d busted a rib or two. I watched Momma steal a look at me and turn tearfully away again. I hated to image how I must look to her with one eye swollen shut, my lip split, and big ugly bruises, yellow and blue, fading at most of my vital spots. Had father put his heart into it, he’d have killed me a dozen times over.
     "I can’t stand what you’re doing to him," Momma said. Stirred by her emotions, her crystal talisman blazed to life, glowing a hard blue. Its energy lifted the soft strands of her hair, pooling in her eyes, sheathing her flesh in Chaos Magic--the heritage of the Silver World to its people.
     "Then look at what I’m doing for him."
     "For him? What’s he supposed to learn from being chained like an animal and starved? That life’s a misery and nothing’s fair?" The fire around Momma brightened.
     "Fair is a word we teach our children when we want the universe to destroy them."
     That’s right Dad, throw a quote from the Edoth at her. She’ll love that.
     "You want to know what I think about that damned book of yours?" Momma’s voice gained amplification as she went along. It was her standard response to father’s logic, but I don’t think I’d ever heard her at this decibel level before. She was getting too bright to look at.

            * 

(Okay, I’ve set up the conflict--a child of two worlds, torn by their separate pulls, needing to find his place in the world.  Now, I need to give the reader background on the cultural forces behind what appears to be cruelty.  I give a brief encapsulated history of my world.)

                 *

"The Edoth is the way of strength. It deserves respect," father answered. "It brought my people out of the jungle, into the light of civilization. It is the code we live and die by, and a path of reason through a pitiless universe. It has enabled my people to survive on a world never meant for life, allowing us to forge paradise from the heart of hell..."
     Hmmmmm, lecture number two-hundred and fifteen. I knew it by heart.
     "If our son is weak, this planet will destroy him. Is that what you want?"
      Their stares were locked. I held my breath. Momma closed her eyes, dropping her head as fresh tears arrived. "No," she answered at last. The fire dancing over her dimmed, subsiding. Her humanity returned.

             *

(Okay, now I’m using the sensory perception of the main character to bring in the alien quality of the world, its uniqueness.)

                  *

I looked at the skylight past open shutters. The crystal port filtered out the harsher bands of radiation, letting a molten bar of light pour into the room. The light brought warmth to murder the morning chill, taking the shiver from my muscles. I was grateful. It was nearly time to end this mess, and I needed all the edge I could get.
     The floor still bore the stains of my last fight.  Splatters marred the patchwork pattern of turquoise, golden agate, beryl, polar jade, and topaz crystal embedded in the plaster deck.  The blood lost distinction as the room became monochromatic--washed a matching crimson by the climbing sun.

            *

(Okay, now it’s time to resolve the situation.  The kid needs to break the deadlock.  A story is conflict, and the ending is the resolution of that conflict.)

            *

 Don’t look down at the missing stone in the fresco, I warned myself. He’ll follow your glance, and see what you’ve done.
     I set my eyes on Father instead, noticing his night-black uniform as it caught a rusty sheen that made it seem soaked in blood. His adamant face glowed like steel in a crucible. His body was massive, hard, as if carved from bedrock.  I love you, Dad, but sometimes,you’re scary as hell.
    My thumb felt the facets of a large topaz hiding in my hand. I’d taken my last beating in order to get it, feigning unconsciousness long after waking up so I could slowly claw it from its plaster setting with small, secretive movements while laying in a deceptive and awkward sprawl.
     This rite-of-passage would have been a lot easier without my off-world blood thinning the strength, speed, and regenerative powers I’d have had were I fully Edothican. Besides which, I had trouble focusing. Like Mother, I tended to question every little thing in the universe. I couldn’t turn it off. A voice inside my head kept asking, what’s the point of starving while chained to a food locker? Is this a test of spirit, intelligence, training...? 
     I’ve had all the usual wilderness survival courses that are designed to measure these things--pushing you past your own assumed limits.  No, I decided, physical force wasn’t the answer here.   Neither was patience or endurance. Father said I’d die before he’d allow me to open the food locker, ending the test. I believed him. I’ve never heard him say anything that wasn’t true one way or another.  He was here on guard duty until I solved the riddle, and could tell him the First Truth--the one damned thing I’d never found mentioned in the Edoth.
I drew a deep breath, and felt no pain. My ribs had knitted. It was time. If I was luckier than I deserved, this trick would work, overloading his reflexive response, bringing him down to my level for a second or two. Within my fist, I shifted the topaz onto my thumbnail, and flicked it into the air. The small motion made my Dad stab me with narrowed eyes, ending his distraction with momma.
     I stood still, projecting innocence as the stone arced high into the air, toward the vaulted ceiling. The cut stone spun, sending refracted star-points of orange light whirling across all surfaces. In that moment, I realized what First Truth had to be: there’s always a way to do what can’t be done. It was a test of imagination.
     Father’s eyes widened slightly as he tracked each movement of light, extrapolating their source. I went in, watching for Father’s reverse kick; he tended to over use it because it was wicked fast, powerful, and got the job done. Time slowed, a trick of the mind that all Edothican children learn early on. I held nothing back, determined to spare Father the burden of becoming my executioner.

              *

(Okay, time for the twist.  The best endings turn things around somewhere on what is expected.  Here, the reader is led to believe that the son is attacking the father, but the next paragraphs stand that assumption on its head.)

              *

     Momma screamed. Dad’s reverse kick came up in a blur as I expected. I hopped on top of his thrusting leg, using his attack to launch my own. My body turned like a wheel. My leg was locked at the knee. This brought my heel arcing down with lethal force. Momma fell back--silenced by sheer surprise. Stunned, she dropped to the floor realizing that she was my target, not father.
     Had she looked closer at the taunt length of chain running from my collar, she’d have known she was safely out of range. So why did I attack her? I knew that only a threat to Mother could draw Father out of position. Yeah, some deep part of him knew the exact length of chain as well as I did, but there was no way he could restrain himself; his heart could not stand to see me commit to a death strike against the woman he loved without him doing something about it.
      I was jerked up short by the chain, hanging myself horizontally by my leap. I dropped like a rock, ignored the pain as best I could. Resisting a sensation of disembodiment, I reached past my head and seized the chain. My back scrapped across the fresco as I reeled myself in, hand over hand, slithering under Father as he sprang toward Momma.
      By the time he overrode his first response; landing, turning, and launching back my way, I’d reached the food locker, and pried it open. Father froze in place glowering down at me. I continued to stuff my mouth with a piece of roasted thunder-lizard haunch, clutching a low-level shelf for support.
      Finally, Father reached into the refrigerated locker for a bottle of purified water. He handed it to me without a word, eyes dancing with amused approval. He smiled for the first time in days as I drained the bottle, and even attempted a joke.
      "Go easy there, Son. Try not to choke on your victory."

             *