I don't borrow. I steal! I then refit it, give it a new paint job and use it how ever I want. For world building so do I steal from everything: works of fiction (books, comics, movies or other doesn't matter); roleplaying games; history books; culture studies; documentaries I see on TV; things that is reported on by the news; computer games; works of art; etc. (B.t.w. I have many and know of many books, movies and similar that can work as inspiration so if people want a suggestion list for what to look up as inspiration for things so could I probably help.) If I see something I like or think I can use, I take it. I then modify it to fit whatever planet/culture/species I thought it would be part of. Then there is also the problem with coming up why the thing is not used more, f.ex. if there is a Force technique that allows you to teleport why have we never seen any jedi or sith use it since they are supposedly the most knowledge Force traditions? Answer: teleportation is highly dangerous and can create havocs around you, therefor not considered worth the price by the jedi or sith, other Force traditions don't know this and teach this technique. Sometime I steal whole cultures/historical periods, f.ex. so is a fic I am working based on a story that take place in Japan's Meiji period and I want to keep as much of the Meiji feeling as possible while at the same time making the country something that are not just Meiji-era Japan with visiting SW characters. I can not really say that I have any real way of making my world-building consistent, as seen in my Force traditions post so are my world-building rather haphazard. Design, the small details and thinking about how the environment and/or species would effect the culture, its technology, design, etc. To me design is highly important when it comes to illustrations, comics and movies but not as important when it is just the written word, where you can get away with descriptions like "the city was made up by cubistic houses in red sandstone". Timothy Zahn is an expert of describing things and people with just a few words. Boring design, the reuse of already existing design or design that don't really fit the description (an all to of the occurring thing in SW) can easily damage the immersion in the story. The small detail are often what makes a culture alive, like what do they eat, how do they great each other, how do they swear (for me this is important, if they are just using something that sound like **** so do I easily lose my immersion), etc. How the environment and/or species being used effect how they think, do things and talk is important if you want something that is not just earth humans (usually westerners) in rubber suits or with a fancy backdrop.