More than anything else, common sense is required to edit Wikipedia.  The careful use of sources, the understanding of how to write lead sections (citations aren't needed in the lead, please see WP:V), the need to verify sources and passages from those sources on the talk page without having to scroll through text (this is the burden of the editor making the claims, please review WP:V), are all part of the process.  Wikipedia:When_to_cite is also helpful here.  Wikipedia:Citation overkill has more to say on this subject as well, when an "editor desperately shores up his point with extra citations, in the hope that his opponents will accept there are reliable sources for his edit."  This appears to be the case here.  The dictionary, Encarta, and writing-world.com, are not what I would consider good sources for the purposes of this article.  And making the claim that science fiction is "usually set in the future" in the very first sentence is a gross (and false) simplification of a complex and multifaceted genre.  I'm getting the strong sense that you haven't really looked into this subject very closely.