Visual inspiration: Ask parents, colleagues, or friends to donate a variety of appropriate magazines. (edutopia.org)
You can also advertise in appropriate magazines — remember the reader is already interested in the subject otherwise they would not have bought the magazine. (ebooksbydesign.co)
For non-fiction a platform is important but you may also have venues - i.e.; you write about hang - gliding, you market thru appropriate magazines, display at meets & conventions, sell in hang - gliding shops, etc.. (accrispin.blogspot.ru)