I’m writing a sci-fi novel and falling into two traps: Infodump and Unobtainium.
Infodump is a when a character gives a mini lecture — telling instead of showing — such as in reply to “Tell me, Professor, how does your invention work?” Infodump can be reduced by editing out any techno-babble, and by using characters to give brief explanations only when plot demands it to move forward.
Unobtainium is a plot device such as an alien substance or a future technology. Most sci-fi has these but too often they’re used by writers to remove a plot hole; as in ‘Lucky I brought my sonic screwdriver to do this impossible task.’ (A version of: ‘Any sufficiently advanced technology is indistinguishable from magic’– Arthur C Clarke). Possible solutions are to make your ‘Unobtainium’ central to the plot (eg. give it a snappy back-story), or reduce it to a playful bit of science.