2. Setting

Otherworlds in fantasy and SF are a special case of setting. You’re not limited to the permanent conditions of our own world, or even similar temporary conditions—you can make up rainbow mist, mud-rain, silvery sunsets. World-creation is one of the special glories of speculative fiction.

The basic principles still apply, though. Whatever you introduce, you have to think through the consequences.

Suppose your world has outcrops of reflective blue stone, hard as diamond. Describing it as a landscape feature is only the first step. You have to ask yourself: what uses would people make of it? (ornaments? spear-tips?) How would it affect farming? or the routing of roadways? Would people build fortifications on the outcrops? or shrines? or leave them deliberately untouched? How would people feel about this special stone? (as something sacred? or something unnatural, to be shunned?) Perhaps it would enter everyday speech in phrases like ‘hard as bluestone’, perhaps it would serve as a symbol of resolution, courage, tenacity …

The perceptual consequences need thinking through too. How would this bluestone look? (in rain? under torchlight?) How would it sound if tapped? How would it smell? (metallic? or complete absence of smell?) What would it be like to touch? (strangely cold? sharp facetted edges?) And again, how would people feel about it? (a usable resource? an alien presence?)

SF writers are sometimes weak on thinking through perceptual consequences; fantasy writers are probably better on perceptual consequences, but sometimes fall down on practical consequences.